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SMD code search: identify a part by its marking

3 parts are printed 1AO. 59 printed with a similar-looking code.

Not sure which one you have?

Answer up to 4 quick questions and these 3 parts are ranked, with a meter test that settles it. It works on a dead part too.

  • 2SC3339-OSOT-23NPN transistor, 3 pins, ToshibaNPN transistorSOT-233 pinsToshiba
    What it is
    NPN transistor
    Maker
    Toshiba
    Package
    SOT-23
    Pins
    3
    Details
    NPN transistor: GP, 60V, 150mA, 150mW, B=70..140, >80MHz
    Source
    Published code list

    Is it dead?

    Diode range, part lifted or its base leg off the pad.

    Working, it reads

    Red probe on the base reads about 0.6 to 0.75 V to the emitter and to the collector, and open the other way round. Collector to emitter reads open both ways.

    Dead, it reads

    • Collector to emitter the same both ways, near 0 V with a continuous beep: shorted. The commonest failure.
    • The base the same both ways to another pin, near 0 V or a middling value: a shorted junction.
    • Only one junction reads, or none: a junction has failed open. It then looks like a diode.
    • A reading the wrong way round, where it should be open: leaky.
    On the board
    this is a first look only: the meter reads every path between those pins, and a short can be a neighbour. Lift one leg before you condemn it.
    Compare:
    If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.
    Watch for:
    A pair of diodes with a common pin reads just like a transistor, and some transistors carry a built-in diode or resistor. The datasheet says which.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

  • 2 more parts have no package on record
    • SGM52410SXURA10G10 pins, SG MicroNot recordedNot recorded10 pinsSG Micro
      What it is
      Not recorded
      Maker
      SG Micro
      Package
      Not recorded
      Pins
      10
      Details
      Low-Power, SPI-Compatible, 24-Bit ADC with Internal Reference and Temperature Sensor
      Source
      Manufacturer datasheet

      Is it dead?

      Voltage with the board powered; ohms from each pin to ground with it off.

      Working, it reads

      Supply pin at its voltage and the output doing what the datasheet says. Readings between pins depend on the part.

      Dead, it reads

      • A pin near 0 Ω to ground or to the supply pin where an identical part does not read that: failed short.
      • Supply present, output stuck: failed, or its load has.
      On the board:
      A pin shorted to ground on the board can be anything on that net. Lift the pin to be sure.
      Compare:
      The surest reference is the same IC on a working board, measured pin by pin.
      Watch for:
      Its protection diodes can read like junctions between pins, even like a transistor. That proves nothing either way.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

    • SGM52410SXURA10SG10 pins, SG MicroNot recordedNot recorded10 pinsSG Micro
      What it is
      Not recorded
      Maker
      SG Micro
      Package
      Not recorded
      Pins
      10
      Details
      Low-Power, SPI-Compatible, 24-Bit ADC with Internal Reference and Temperature Sensor
      Source
      Manufacturer datasheet

      Is it dead?

      Voltage with the board powered; ohms from each pin to ground with it off.

      Working, it reads

      Supply pin at its voltage and the output doing what the datasheet says. Readings between pins depend on the part.

      Dead, it reads

      • A pin near 0 Ω to ground or to the supply pin where an identical part does not read that: failed short.
      • Supply present, output stuck: failed, or its load has.
      On the board:
      A pin shorted to ground on the board can be anything on that net. Lift the pin to be sure.
      Compare:
      The surest reference is the same IC on a working board, measured pin by pin.
      Watch for:
      Its protection diodes can read like junctions between pins, even like a transistor. That proves nothing either way.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

59 more parts are printed with a code easy to misread as 1AO

Printed with a code easy to misread

One character differs, and it is one that is easy to confuse under a lamp. The odd one out is marked on each.

  • BRBC846Qprinted 1AQSOT-23NPN transistor, 3 pins, Blue RocketNPN transistorSOT-233 pinsBlue Rocket

    Printed 1AQ on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

    What it is
    NPN transistor
    Maker
    Blue Rocket
    Package
    SOT-23
    Pins
    3
    Details
    NPN bipolar transistor
    Source
    Manufacturer datasheet

    Is it dead?

    Diode range, part lifted or its base leg off the pad.

    Working, it reads

    Red probe on the base reads about 0.6 to 0.75 V to the emitter and to the collector, and open the other way round. Collector to emitter reads open both ways.

    Dead, it reads

    • Collector to emitter the same both ways, near 0 V with a continuous beep: shorted. The commonest failure.
    • The base the same both ways to another pin, near 0 V or a middling value: a shorted junction.
    • Only one junction reads, or none: a junction has failed open. It then looks like a diode.
    • A reading the wrong way round, where it should be open: leaky.
    On the board
    this is a first look only: the meter reads every path between those pins, and a short can be a neighbour. Lift one leg before you condemn it.
    Compare:
    If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.
    Watch for:
    A pair of diodes with a common pin reads just like a transistor, and some transistors carry a built-in diode or resistor. The datasheet says which.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

  • NCP551SN15printed LAOSOT-23-5LDO regulator, 5 pins, onsemiLDO regulatorSOT-23-55 pinsonsemi

    Printed LAO on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

    What it is
    LDO regulator
    Maker
    onsemi
    Package
    SOT-23-5
    Pins
    5
    Details
    Voltage Regulator - CMOS, - Low Iq, Low Dropout
    Source
    Manufacturer datasheet

    Is it dead?

    Voltage, board powered, black probe on ground. Then ohms with the power off.

    Working, it reads

    Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

    Dead, it reads

    • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
    • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
    • Power off, input to output near 0 Ω: shorted.
    On the board:
    An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
    Compare:
    The same regulator on another rail or another board shows the right voltages and the right resistances.
    Watch for:
    Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

  • NCP551SN25printed LAQSOT-23-5LDO regulator, 5 pins, onsemiLDO regulatorSOT-23-55 pinsonsemi

    Printed LAQ on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

    What it is
    LDO regulator
    Maker
    onsemi
    Package
    SOT-23-5
    Pins
    5
    Details
    Voltage Regulator - CMOS, - Low Iq, Low Dropout
    Source
    Manufacturer datasheet

    Is it dead?

    Voltage, board powered, black probe on ground. Then ohms with the power off.

    Working, it reads

    Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

    Dead, it reads

    • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
    • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
    • Power off, input to output near 0 Ω: shorted.
    On the board:
    An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
    Compare:
    The same regulator on another rail or another board shows the right voltages and the right resistances.
    Watch for:
    Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

  • 1KSMB9V1A-TGprinted IADSMBTVS diode, 2 pins, Fagor ElectronicaTVS diodeSMB2 pinsFagor Electronica

    Printed IAD on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

    What it is
    TVS diode
    Maker
    Fagor Electronica
    Package
    SMB
    Pins
    2
    Details
    Transient voltage supressor: Vrwm=7.78V, Vbr=8.65..9.55V, 74.6A, 1000W(1ms)
    Source
    Published code list

    Is it dead?

    Diode range, from the protected line to ground, part lifted if you can.

    Working, it reads

    A one-way part reads about 0.6 to 0.8 V forward and open in reverse. A two-way part reads open both ways. Arrays with several lines read as the datasheet's diagram draws them.

    Dead, it reads

    • From the line to ground, the same reading both ways, near 0 V with a continuous beep: shorted.
    • A reading both ways on a one-way part: leaky.
    • A one-way part open both ways: failed open.
    On the board
    , a line reading shorted to ground can be this part or anything else on that line. Lift it: if the short goes with it, it has failed.
    Compare:
    The same part on the next line or connector pin is the healthy reading to compare with.
    Watch for:
    A two-way part reads open both ways when it is good, exactly like one that has failed open. The meter cannot tell them apart; an identical part on the next line can.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

  • 1KSMB27A-TGprinted IAOSMBTVS diode, 2 pins, Fagor ElectronicaTVS diodeSMB2 pinsFagor Electronica

    Printed IAO on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

    What it is
    TVS diode
    Maker
    Fagor Electronica
    Package
    SMB
    Pins
    2
    Details
    Transient voltage supressor: Vrwm=23.10V, Vbr=25.70..28.40V, 26.7A, 1000W(1ms)
    Source
    Published code list

    Is it dead?

    Diode range, from the protected line to ground, part lifted if you can.

    Working, it reads

    A one-way part reads about 0.6 to 0.8 V forward and open in reverse. A two-way part reads open both ways. Arrays with several lines read as the datasheet's diagram draws them.

    Dead, it reads

    • From the line to ground, the same reading both ways, near 0 V with a continuous beep: shorted.
    • A reading both ways on a one-way part: leaky.
    • A one-way part open both ways: failed open.
    On the board
    , a line reading shorted to ground can be this part or anything else on that line. Lift it: if the short goes with it, it has failed.
    Compare:
    The same part on the next line or connector pin is the healthy reading to compare with.
    Watch for:
    A two-way part reads open both ways when it is good, exactly like one that has failed open. The meter cannot tell them apart; an identical part on the next line can.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

  • 1KSMB33A-TGprinted IAQSMBTVS diode, 2 pins, Fagor ElectronicaTVS diodeSMB2 pinsFagor Electronica

    Printed IAQ on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

    What it is
    TVS diode
    Maker
    Fagor Electronica
    Package
    SMB
    Pins
    2
    Details
    Transient voltage supressor: Vrwm=28.20V, Vbr=31.40..34.70V, 21.9A, 1000W(1ms)
    Source
    Published code list

    Is it dead?

    Diode range, from the protected line to ground, part lifted if you can.

    Working, it reads

    A one-way part reads about 0.6 to 0.8 V forward and open in reverse. A two-way part reads open both ways. Arrays with several lines read as the datasheet's diagram draws them.

    Dead, it reads

    • From the line to ground, the same reading both ways, near 0 V with a continuous beep: shorted.
    • A reading both ways on a one-way part: leaky.
    • A one-way part open both ways: failed open.
    On the board
    , a line reading shorted to ground can be this part or anything else on that line. Lift it: if the short goes with it, it has failed.
    Compare:
    The same part on the next line or connector pin is the healthy reading to compare with.
    Watch for:
    A two-way part reads open both ways when it is good, exactly like one that has failed open. The meter cannot tell them apart; an identical part on the next line can.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

  • 2SB0779-Qprinted 1AQSOT-23PNP transistor, 3 pins, PanasonicPNP transistorSOT-233 pinsPanasonic

    Printed 1AQ on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

    What it is
    PNP transistor
    Maker
    Panasonic
    Package
    SOT-23
    Pins
    3
    Details
    PNP transistor: AF-Drv, 25V, 500mA, 200mW, B=90..155, 150MHz
    Source
    Published code list

    Is it dead?

    Diode range, part lifted or its base leg off the pad.

    Working, it reads

    Black probe on the base reads about 0.6 to 0.75 V to the emitter and to the collector, and open the other way round. Collector to emitter reads open both ways.

    Dead, it reads

    • Collector to emitter the same both ways, near 0 V with a continuous beep: shorted. The commonest failure.
    • The base the same both ways to another pin, near 0 V or a middling value: a shorted junction.
    • Only one junction reads, or none: a junction has failed open. It then looks like a diode.
    • A reading the wrong way round, where it should be open: leaky.
    On the board
    this is a first look only: the meter reads every path between those pins, and a short can be a neighbour. Lift one leg before you condemn it.
    Compare:
    If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.
    Watch for:
    A pair of diodes with a common pin reads just like a transistor, and some transistors carry a built-in diode or resistor. The datasheet says which.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

  • 2SB779-Qprinted 1AQSOT-233 pins, PanNot recordedSOT-233 pinsPan

    Printed 1AQ on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

    What it is
    Not recorded
    Maker
    Pan
    Package
    SOT-23
    Pins
    3
    Details
    Si-pnp: AF-Drv, 25V, 500mA, 200mW, B=90..155, 150MHz
    Source
    Published code list

    Is it dead?

    Diode range and ohms range, part lifted.

    Working, it reads

    Depends on what it is. The datasheet, or an identical part, says.

    Dead, it reads

    • Between two pins, the same reading both ways, near 0 V with a continuous beep: shorted.
    • Open between every pair of pins: failed open, or a part that reads open when working.
    On the board
    this is a first look only: the meter reads every path between those pins, and a short can be a neighbour. Lift one leg before you condemn it.
    Compare:
    If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

  • 2SB1584-Qprinted 1AQSOT-4163 pins, PanasonicNot recordedSOT-4163 pinsPanasonic

    Printed 1AQ on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

    What it is
    Not recorded
    Maker
    Panasonic
    Package
    SOT-416
    Pins
    3
    Details
    Si-pnp: Lo-sat, 25V, 500mA, 150MHz, B=85..170
    Source
    Published code list

    Is it dead?

    Diode range and ohms range, part lifted.

    Working, it reads

    Depends on what it is. The datasheet, or an identical part, says.

    Dead, it reads

    • Between two pins, the same reading both ways, near 0 V with a continuous beep: shorted.
    • Open between every pair of pins: failed open, or a part that reads open when working.
    On the board
    this is a first look only: the meter reads every path between those pins, and a short can be a neighbour. Lift one leg before you condemn it.
    Compare:
    If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

  • ADM6326-22ARTZprinted LAQSOT-23Voltage supervisor, 3 pins, Analog DevicesVoltage supervisorSOT-233 pinsAnalog Devices

    Printed LAQ on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

    What it is
    Voltage supervisor
    Maker
    Analog Devices
    Package
    SOT-23
    Pins
    3
    Details
    Voltage detector IC: 2.2V±2.5%, -Reset PPO
    Source
    Published code list

    Is it dead?

    Voltage with the board powered; ohms from each pin to ground with it off.

    Working, it reads

    Supply pin at its voltage and the output doing what the datasheet says. Readings between pins depend on the part.

    Dead, it reads

    • A pin near 0 Ω to ground or to the supply pin where an identical part does not read that: failed short.
    • Supply present, output stuck: failed, or its load has.
    On the board:
    A pin shorted to ground on the board can be anything on that net. Lift the pin to be sure.
    Compare:
    The surest reference is the same IC on a working board, measured pin by pin.
    Watch for:
    Its protection diodes can read like junctions between pins, even like a transistor. That proves nothing either way.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

  • HM624510PRprinted 1A0SOT-89LDO regulator, 3 pins, Huamei SemiconductorLDO regulatorSOT-893 pinsHuamei Semiconductor

    Printed 1A0 on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

    What it is
    LDO regulator
    Maker
    Huamei Semiconductor
    Package
    SOT-89
    Pins
    3
    Details
    Linear voltage regulator IC: LDO, 1.1V±2%, 1A
    Source
    Published code list

    Is it dead?

    Voltage, board powered, black probe on ground. Then ohms with the power off.

    Working, it reads

    Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

    Dead, it reads

    • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
    • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
    • Power off, input to output near 0 Ω: shorted.
    On the board:
    An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
    Compare:
    The same regulator on another rail or another board shows the right voltages and the right resistances.
    Watch for:
    Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

  • IXD1415AAA0ER-Gprinted 1A0USP-6CLDO regulator, 6 pins, IXYSLDO regulatorUSP-6C6 pinsIXYS

    Printed 1A0 on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

    What it is
    LDO regulator
    Maker
    IXYS
    Package
    USP-6C
    Pins
    6
    Details
    Linear voltage regulator IC: LDO, Dual out, Vout1/Vout2=3.10/1.80V±1%, 200mA, +CE
    Source
    Published code list

    Is it dead?

    Voltage, board powered, black probe on ground. Then ohms with the power off.

    Working, it reads

    Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

    Dead, it reads

    • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
    • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
    • Power off, input to output near 0 Ω: shorted.
    On the board:
    An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
    Compare:
    The same regulator on another rail or another board shows the right voltages and the right resistances.
    Watch for:
    Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

  • IXD1415AAA0MRprinted 1A0SOT-23-6LDO regulator, 6 pins, IXYSLDO regulatorSOT-23-66 pinsIXYS

    Printed 1A0 on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

    What it is
    LDO regulator
    Maker
    IXYS
    Package
    SOT-23-6
    Pins
    6
    Details
    Linear voltage regulator IC: LDO, Dual out, Vout1/Vout2=3.10/1.80V±1%, 200mA, +CE
    Source
    Published code list

    Is it dead?

    Voltage, board powered, black probe on ground. Then ohms with the power off.

    Working, it reads

    Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

    Dead, it reads

    • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
    • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
    • Power off, input to output near 0 Ω: shorted.
    On the board:
    An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
    Compare:
    The same regulator on another rail or another board shows the right voltages and the right resistances.
    Watch for:
    Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

  • IXD1602A051ER-Gprinted 1A0USP-6CLDO regulator, 6 pins, IXYSLDO regulatorUSP-6C6 pinsIXYS

    Printed 1A0 on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

    What it is
    LDO regulator
    Maker
    IXYS
    Package
    USP-6C
    Pins
    6
    Details
    Linear voltage regulator IC: LDO, 0.5V±15mV, 1A, +CE, soft start
    Source
    Published code list

    Is it dead?

    Voltage, board powered, black probe on ground. Then ohms with the power off.

    Working, it reads

    Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

    Dead, it reads

    • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
    • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
    • Power off, input to output near 0 Ω: shorted.
    On the board:
    An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
    Compare:
    The same regulator on another rail or another board shows the right voltages and the right resistances.
    Watch for:
    Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

  • IXD1602A051PR-Gprinted 1A0SOT-89-5LDO regulator, 5 pins, IXYSLDO regulatorSOT-89-55 pinsIXYS

    Printed 1A0 on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

    What it is
    LDO regulator
    Maker
    IXYS
    Package
    SOT-89-5
    Pins
    5
    Details
    Linear voltage regulator IC: LDO, 0.5V±15mV, 1A, +CE, soft start
    Source
    Published code list

    Is it dead?

    Voltage, board powered, black probe on ground. Then ohms with the power off.

    Working, it reads

    Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

    Dead, it reads

    • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
    • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
    • Power off, input to output near 0 Ω: shorted.
    On the board:
    An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
    Compare:
    The same regulator on another rail or another board shows the right voltages and the right resistances.
    Watch for:
    Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

  • IXD1602A181ER-Gprinted 1ADUSP-6CLDO regulator, 6 pins, IXYSLDO regulatorUSP-6C6 pinsIXYS

    Printed 1AD on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

    What it is
    LDO regulator
    Maker
    IXYS
    Package
    USP-6C
    Pins
    6
    Details
    Linear voltage regulator IC: LDO, 1.8V±20mV, 1A, +CE, soft start
    Source
    Published code list

    Is it dead?

    Voltage, board powered, black probe on ground. Then ohms with the power off.

    Working, it reads

    Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

    Dead, it reads

    • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
    • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
    • Power off, input to output near 0 Ω: shorted.
    On the board:
    An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
    Compare:
    The same regulator on another rail or another board shows the right voltages and the right resistances.
    Watch for:
    Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

  • IXD1602A181PR-Gprinted 1ADSOT-89-5LDO regulator, 5 pins, IXYSLDO regulatorSOT-89-55 pinsIXYS

    Printed 1AD on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

    What it is
    LDO regulator
    Maker
    IXYS
    Package
    SOT-89-5
    Pins
    5
    Details
    Linear voltage regulator IC: LDO, 1.8V±20mV, 1A, +CE, soft start
    Source
    Published code list

    Is it dead?

    Voltage, board powered, black probe on ground. Then ohms with the power off.

    Working, it reads

    Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

    Dead, it reads

    • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
    • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
    • Power off, input to output near 0 Ω: shorted.
    On the board:
    An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
    Compare:
    The same regulator on another rail or another board shows the right voltages and the right resistances.
    Watch for:
    Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

  • MIC5213-2.6BC5printed LAQSOT-23-55 pins, MicrochipNot recordedSOT-23-55 pinsMicrochip

    Printed LAQ on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

    What it is
    Not recorded
    Maker
    Microchip
    Package
    SOT-23-5
    Pins
    5
    Details
    VR-IC: LDO, CE, 2,6V±3%, 150mA
    Source
    Published code list

    Is it dead?

    Voltage, board powered, black probe on ground. Then ohms with the power off.

    Working, it reads

    Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

    Dead, it reads

    • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
    • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
    • Power off, input to output near 0 Ω: shorted.
    On the board:
    An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
    Compare:
    The same regulator on another rail or another board shows the right voltages and the right resistances.
    Watch for:
    Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

  • MIC5213-2.6YC5printed LAQSOT-353LDO regulator, 5 pins, MicrelLDO regulatorSOT-3535 pinsMicrel

    Printed LAQ on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

    What it is
    LDO regulator
    Maker
    Micrel
    Package
    SOT-353
    Pins
    5
    Details
    Linear voltage regulator IC: LDO, 2.6V±3%, 150mA, +CE, Pb-free
    Source
    Published code list

    Is it dead?

    Voltage, board powered, black probe on ground. Then ohms with the power off.

    Working, it reads

    Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

    Dead, it reads

    • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
    • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
    • Power off, input to output near 0 Ω: shorted.
    On the board:
    An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
    Compare:
    The same regulator on another rail or another board shows the right voltages and the right resistances.
    Watch for:
    Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

  • MIC5213-3.6BC5printed LADSOT-23-55 pins, MicrochipNot recordedSOT-23-55 pinsMicrochip

    Printed LAD on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

    What it is
    Not recorded
    Maker
    Microchip
    Package
    SOT-23-5
    Pins
    5
    Details
    VR-IC: LDO, CE, 3,6V±3%, 150mA
    Source
    Published code list

    Is it dead?

    Voltage, board powered, black probe on ground. Then ohms with the power off.

    Working, it reads

    Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

    Dead, it reads

    • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
    • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
    • Power off, input to output near 0 Ω: shorted.
    On the board:
    An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
    Compare:
    The same regulator on another rail or another board shows the right voltages and the right resistances.
    Watch for:
    Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

  • MIC5213-3.6YC5printed LADSOT-353LDO regulator, 5 pins, MicrelLDO regulatorSOT-3535 pinsMicrel

    Printed LAD on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

    What it is
    LDO regulator
    Maker
    Micrel
    Package
    SOT-353
    Pins
    5
    Details
    Linear voltage regulator IC: LDO, 3.6V±3%, 150mA, +CE, Pb-free
    Source
    Published code list

    Is it dead?

    Voltage, board powered, black probe on ground. Then ohms with the power off.

    Working, it reads

    Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

    Dead, it reads

    • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
    • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
    • Power off, input to output near 0 Ω: shorted.
    On the board:
    An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
    Compare:
    The same regulator on another rail or another board shows the right voltages and the right resistances.
    Watch for:
    Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

  • NCP551SN15T1printed LAOSOT-353LDO regulator, 5 pins, onsemiLDO regulatorSOT-3535 pinsonsemi

    Printed LAO on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

    What it is
    LDO regulator
    Maker
    onsemi
    Package
    SOT-353
    Pins
    5
    Details
    VR-IC: LDO, Low Iq, CE, 1,5V±2%, 150mA
    Source
    Published code list

    Is it dead?

    Voltage, board powered, black probe on ground. Then ohms with the power off.

    Working, it reads

    Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

    Dead, it reads

    • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
    • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
    • Power off, input to output near 0 Ω: shorted.
    On the board:
    An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
    Compare:
    The same regulator on another rail or another board shows the right voltages and the right resistances.
    Watch for:
    Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

  • NCP551SN25T1printed LAQSOT-353LDO regulator, 5 pins, onsemiLDO regulatorSOT-3535 pinsonsemi

    Printed LAQ on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

    What it is
    LDO regulator
    Maker
    onsemi
    Package
    SOT-353
    Pins
    5
    Details
    VR-IC: LDO, Low Iq, CE, 2,5V±2%, 150mA
    Source
    Published code list

    Is it dead?

    Voltage, board powered, black probe on ground. Then ohms with the power off.

    Working, it reads

    Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

    Dead, it reads

    • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
    • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
    • Power off, input to output near 0 Ω: shorted.
    On the board:
    An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
    Compare:
    The same regulator on another rail or another board shows the right voltages and the right resistances.
    Watch for:
    Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

  • NCP551SN25T1Gprinted LAQSOT-23-5LDO regulator, 5 pins, onsemiLDO regulatorSOT-23-55 pinsonsemi

    Printed LAQ on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

    What it is
    LDO regulator
    Maker
    onsemi
    Package
    SOT-23-5
    Pins
    5
    Source
    Published code list

    Is it dead?

    Voltage, board powered, black probe on ground. Then ohms with the power off.

    Working, it reads

    Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

    Dead, it reads

    • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
    • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
    • Power off, input to output near 0 Ω: shorted.
    On the board:
    An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
    Compare:
    The same regulator on another rail or another board shows the right voltages and the right resistances.
    Watch for:
    Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

  • RP124N253Bprinted 1ADSOT-23-5LDO regulator, 5 pins, RicohLDO regulatorSOT-23-55 pinsRicoh

    Printed 1AD on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

    What it is
    LDO regulator
    Maker
    Ricoh
    Package
    SOT-23-5
    Pins
    5
    Details
    Linear voltage regulator IC: LDO, 2.5V±0.8%, 100mA, +CE, BM=Vin/3
    Source
    Published code list

    Is it dead?

    Voltage, board powered, black probe on ground. Then ohms with the power off.

    Working, it reads

    Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

    Dead, it reads

    • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
    • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
    • Power off, input to output near 0 Ω: shorted.
    On the board:
    An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
    Compare:
    The same regulator on another rail or another board shows the right voltages and the right resistances.
    Watch for:
    Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

  • RP171N601Bprinted LADSOT-23-5LDO regulator, 5 pins, RicohLDO regulatorSOT-23-55 pinsRicoh

    Printed LAD on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

    What it is
    LDO regulator
    Maker
    Ricoh
    Package
    SOT-23-5
    Pins
    5
    Details
    Linear voltage regulator IC: LDO, 6.0V±1%, 150mA, +CE
    Source
    Published code list

    Is it dead?

    Voltage, board powered, black probe on ground. Then ohms with the power off.

    Working, it reads

    Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

    Dead, it reads

    • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
    • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
    • Power off, input to output near 0 Ω: shorted.
    On the board:
    An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
    Compare:
    The same regulator on another rail or another board shows the right voltages and the right resistances.
    Watch for:
    Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

  • S-8540A18FN-IADT2printed IADMSOP-88 pins, ABLICNot recordedMSOP-88 pinsABLIC

    Printed IAD on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

    What it is
    Not recorded
    Maker
    ABLIC
    Package
    MSOP-8
    Pins
    8
    Source
    Published code list

    Is it dead?

    Diode range and ohms range, part lifted.

    Working, it reads

    Depends on what it is. The datasheet, or an identical part, says.

    Dead, it reads

    • Between two pins, the same reading both ways, near 0 V with a continuous beep: shorted.
    • Open between every pair of pins: failed open, or a part that reads open when working.
    On the board
    this is a first look only: the meter reads every path between those pins, and a short can be a neighbour. Lift one leg before you condemn it.
    Compare:
    If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

  • SMB8J5.0Cprinted 1ADSMBTVS diode, 2 pins, VishayTVS diodeSMB2 pinsVishay

    Printed 1AD on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

    What it is
    TVS diode
    Maker
    Vishay
    Package
    SMB
    Pins
    2
    Details
    TVS: Vbr=6.40..7.82V, Vvm=5.0V, 83.3A, 1000W(1ms), Bidir.
    Source
    Published code list

    Is it dead?

    Diode range, from the protected line to ground, part lifted if you can.

    Working, it reads

    A one-way part reads about 0.6 to 0.8 V forward and open in reverse. A two-way part reads open both ways. Arrays with several lines read as the datasheet's diagram draws them.

    Dead, it reads

    • From the line to ground, the same reading both ways, near 0 V with a continuous beep: shorted.
    • A reading both ways on a one-way part: leaky.
    • A one-way part open both ways: failed open.
    On the board
    , a line reading shorted to ground can be this part or anything else on that line. Lift it: if the short goes with it, it has failed.
    Compare:
    The same part on the next line or connector pin is the healthy reading to compare with.
    Watch for:
    A two-way part reads open both ways when it is good, exactly like one that has failed open. The meter cannot tell them apart; an identical part on the next line can.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

  • SMB8J8.0Cprinted 1AQSMBTVS diode, 2 pins, VishayTVS diodeSMB2 pinsVishay

    Printed 1AQ on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

    What it is
    TVS diode
    Maker
    Vishay
    Package
    SMB
    Pins
    2
    Details
    TVS: Vbr=8.89..10.9V, Vvm=8.0V, 53.3A, 1000W(1ms), Bidir.
    Source
    Published code list

    Is it dead?

    Diode range, from the protected line to ground, part lifted if you can.

    Working, it reads

    A one-way part reads about 0.6 to 0.8 V forward and open in reverse. A two-way part reads open both ways. Arrays with several lines read as the datasheet's diagram draws them.

    Dead, it reads

    • From the line to ground, the same reading both ways, near 0 V with a continuous beep: shorted.
    • A reading both ways on a one-way part: leaky.
    • A one-way part open both ways: failed open.
    On the board
    , a line reading shorted to ground can be this part or anything else on that line. Lift it: if the short goes with it, it has failed.
    Compare:
    The same part on the next line or connector pin is the healthy reading to compare with.
    Watch for:
    A two-way part reads open both ways when it is good, exactly like one that has failed open. The meter cannot tell them apart; an identical part on the next line can.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

  • SMB10J5.0printed 1ADSMATVS diode, 2 pins, VishayTVS diodeSMA2 pinsVishay

    Printed 1AD on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

    What it is
    TVS diode
    Maker
    Vishay
    Package
    SMA
    Pins
    2
    Details
    TVS: Vbr=6.40..7.82V, Vvm=5.0V, 104.2A, 1000W(1ms)
    Source
    Published code list

    Is it dead?

    Diode range, from the protected line to ground, part lifted if you can.

    Working, it reads

    A one-way part reads about 0.6 to 0.8 V forward and open in reverse. A two-way part reads open both ways. Arrays with several lines read as the datasheet's diagram draws them.

    Dead, it reads

    • From the line to ground, the same reading both ways, near 0 V with a continuous beep: shorted.
    • A reading both ways on a one-way part: leaky.
    • A one-way part open both ways: failed open.
    On the board
    , a line reading shorted to ground can be this part or anything else on that line. Lift it: if the short goes with it, it has failed.
    Compare:
    The same part on the next line or connector pin is the healthy reading to compare with.
    Watch for:
    A two-way part reads open both ways when it is good, exactly like one that has failed open. The meter cannot tell them apart; an identical part on the next line can.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

  • SMB10J8.0printed 1AQSMBTVS diode, 2 pins, VishayTVS diodeSMB2 pinsVishay

    Printed 1AQ on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

    What it is
    TVS diode
    Maker
    Vishay
    Package
    SMB
    Pins
    2
    Details
    TVS: Vbr=8.89..10.9V, Vvm=8.0V, 66.7A, 1000W(1ms)
    Source
    Published code list

    Is it dead?

    Diode range, from the protected line to ground, part lifted if you can.

    Working, it reads

    A one-way part reads about 0.6 to 0.8 V forward and open in reverse. A two-way part reads open both ways. Arrays with several lines read as the datasheet's diagram draws them.

    Dead, it reads

    • From the line to ground, the same reading both ways, near 0 V with a continuous beep: shorted.
    • A reading both ways on a one-way part: leaky.
    • A one-way part open both ways: failed open.
    On the board
    , a line reading shorted to ground can be this part or anything else on that line. Lift it: if the short goes with it, it has failed.
    Compare:
    The same part on the next line or connector pin is the healthy reading to compare with.
    Watch for:
    A two-way part reads open both ways when it is good, exactly like one that has failed open. The meter cannot tell them apart; an identical part on the next line can.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

  • XC2211A1100Mprinted 1A0SOT-23-5Operational amplifier, 5 pins, TorexOperational amplifierSOT-23-55 pinsTorex

    Printed 1A0 on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

    What it is
    Operational amplifier
    Maker
    Torex
    Package
    SOT-23-5
    Pins
    5
    Details
    Op-IC: µPow, ±0,6..±5V, Icco=15µA, 550KHz, 0,5V/µs
    Source
    Published code list

    Is it dead?

    Voltage with the board powered; ohms from each pin to ground with it off.

    Working, it reads

    Supply pin at its voltage and the output doing what the datasheet says. Readings between pins depend on the part.

    Dead, it reads

    • A pin near 0 Ω to ground or to the supply pin where an identical part does not read that: failed short.
    • Supply present, output stuck: failed, or its load has.
    On the board:
    A pin shorted to ground on the board can be anything on that net. Lift the pin to be sure.
    Compare:
    The surest reference is the same IC on a working board, measured pin by pin.
    Watch for:
    Its protection diodes can read like junctions between pins, even like a transistor. That proves nothing either way.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

  • XC6102B631MRprinted 1A0SOT-23-5Voltage supervisor, 5 pins, TorexVoltage supervisorSOT-23-55 pinsTorex

    Printed 1A0 on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

    What it is
    Voltage supervisor
    Maker
    Torex
    Package
    SOT-23-5
    Pins
    5
    Details
    CMOS-IC: VDet 3.1V, 5%, Hst, -MR, -Reset ODO, Wt=1.6s, Rt=25ms
    Source
    Published code list

    Is it dead?

    Voltage with the board powered; ohms from each pin to ground with it off.

    Working, it reads

    Supply pin at its voltage and the output doing what the datasheet says. Readings between pins depend on the part.

    Dead, it reads

    • A pin near 0 Ω to ground or to the supply pin where an identical part does not read that: failed short.
    • Supply present, output stuck: failed, or its load has.
    On the board:
    A pin shorted to ground on the board can be anything on that net. Lift the pin to be sure.
    Compare:
    The surest reference is the same IC on a working board, measured pin by pin.
    Watch for:
    Its protection diodes can read like junctions between pins, even like a transistor. That proves nothing either way.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

  • XC6102B644MRprinted 1ADSOT-23-5Voltage supervisor, 5 pins, TorexVoltage supervisorSOT-23-55 pinsTorex

    Printed 1AD on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

    What it is
    Voltage supervisor
    Maker
    Torex
    Package
    SOT-23-5
    Pins
    5
    Details
    CMOS-IC: VDet 4.4V, 5%, Hst, -MR, -Reset ODO, Wt=1.6s, Rt=25ms
    Source
    Published code list

    Is it dead?

    Voltage with the board powered; ohms from each pin to ground with it off.

    Working, it reads

    Supply pin at its voltage and the output doing what the datasheet says. Readings between pins depend on the part.

    Dead, it reads

    • A pin near 0 Ω to ground or to the supply pin where an identical part does not read that: failed short.
    • Supply present, output stuck: failed, or its load has.
    On the board:
    A pin shorted to ground on the board can be anything on that net. Lift the pin to be sure.
    Compare:
    The surest reference is the same IC on a working board, measured pin by pin.
    Watch for:
    Its protection diodes can read like junctions between pins, even like a transistor. That proves nothing either way.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

  • XC6217A14AMRprinted 1ADSOT-23-5LDO regulator, 5 pins, TorexLDO regulatorSOT-23-55 pinsTorex

    Printed 1AD on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

    What it is
    LDO regulator
    Maker
    Torex
    Package
    SOT-23-5
    Pins
    5
    Details
    VR-IC: LDO, -CE, Sdwn, 1.45V±2%, 200mA
    Source
    Published code list

    Is it dead?

    Voltage, board powered, black probe on ground. Then ohms with the power off.

    Working, it reads

    Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

    Dead, it reads

    • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
    • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
    • Power off, input to output near 0 Ω: shorted.
    On the board:
    An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
    Compare:
    The same regulator on another rail or another board shows the right voltages and the right resistances.
    Watch for:
    Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

  • XC6219A312MRprinted LA0SOT-23-5LDO regulator, 5 pins, TorexLDO regulatorSOT-23-55 pinsTorex

    Printed LA0 on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

    What it is
    LDO regulator
    Maker
    Torex
    Package
    SOT-23-5
    Pins
    5
    Details
    VR-IC: LDO, CE, int. pull-dwn res., 3.1V±2%, 240mA
    Source
    Published code list

    Is it dead?

    Voltage, board powered, black probe on ground. Then ohms with the power off.

    Working, it reads

    Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

    Dead, it reads

    • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
    • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
    • Power off, input to output near 0 Ω: shorted.
    On the board:
    An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
    Compare:
    The same regulator on another rail or another board shows the right voltages and the right resistances.
    Watch for:
    Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

  • 11 more parts have no package on record
    • ADP2108ACBZ-1.8-R7printed LAD5 pins, Analog DevicesNot recordedNot recorded5 pinsAnalog Devices

      Printed LAD on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

      What it is
      Not recorded
      Maker
      Analog Devices
      Package
      Not recorded
      Pins
      5
      Details
      equivalent [1.8V DC]
      Source
      Published code list

      Is it dead?

      Diode range and ohms range, part lifted.

      Working, it reads

      Depends on what it is. The datasheet, or an identical part, says.

      Dead, it reads

      • Between two pins, the same reading both ways, near 0 V with a continuous beep: shorted.
      • Open between every pair of pins: failed open, or a part that reads open when working.
      On the board
      this is a first look only: the meter reads every path between those pins, and a short can be a neighbour. Lift one leg before you condemn it.
      Compare:
      If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

    • ADP2108AUJZ-1.8-R7printed LAD5 pins, Analog DevicesNot recordedNot recorded5 pinsAnalog Devices

      Printed LAD on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

      What it is
      Not recorded
      Maker
      Analog Devices
      Package
      Not recorded
      Pins
      5
      Details
      equivalent [1.8V DC]
      Source
      Published code list

      Is it dead?

      Diode range and ohms range, part lifted.

      Working, it reads

      Depends on what it is. The datasheet, or an identical part, says.

      Dead, it reads

      • Between two pins, the same reading both ways, near 0 V with a continuous beep: shorted.
      • Open between every pair of pins: failed open, or a part that reads open when working.
      On the board
      this is a first look only: the meter reads every path between those pins, and a short can be a neighbour. Lift one leg before you condemn it.
      Compare:
      If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

    • ADP2503ACPZ-4.2-R7printed LA010 pins, Analog DevicesNot recordedNot recorded10 pinsAnalog Devices

      Printed LA0 on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

      What it is
      Not recorded
      Maker
      Analog Devices
      Package
      Not recorded
      Pins
      10
      Details
      equivalent [4.2V DC]
      Source
      Published code list

      Is it dead?

      Diode range and ohms range, part lifted.

      Working, it reads

      Depends on what it is. The datasheet, or an identical part, says.

      Dead, it reads

      • Between two pins, the same reading both ways, near 0 V with a continuous beep: shorted.
      • Open between every pair of pins: failed open, or a part that reads open when working.
      On the board
      this is a first look only: the meter reads every path between those pins, and a short can be a neighbour. Lift one leg before you condemn it.
      Compare:
      If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

    • IXD1415AAA07R-Gprinted 1A0LDO regulator, IXYSLDO regulatorNot recordedNot recordedIXYS

      Printed 1A0 on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

      What it is
      LDO regulator
      Maker
      IXYS
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Linear voltage regulator IC: LDO, Dual out, Vout1/Vout2=3.10/1.80V±1%, 200mA, +CE
      Source
      Published code list

      Is it dead?

      Voltage, board powered, black probe on ground. Then ohms with the power off.

      Working, it reads

      Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

      Dead, it reads

      • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
      • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
      • Power off, input to output near 0 Ω: shorted.
      On the board:
      An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
      Compare:
      The same regulator on another rail or another board shows the right voltages and the right resistances.
      Watch for:
      Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

    • IXD1602A0510R-Gprinted 1A0LDO regulator, IXYSLDO regulatorNot recordedNot recordedIXYS

      Printed 1A0 on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

      What it is
      LDO regulator
      Maker
      IXYS
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Linear voltage regulator IC: LDO, 0.5V±15mV, 1A, +CE, soft start
      Source
      Published code list

      Is it dead?

      Voltage, board powered, black probe on ground. Then ohms with the power off.

      Working, it reads

      Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

      Dead, it reads

      • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
      • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
      • Power off, input to output near 0 Ω: shorted.
      On the board:
      An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
      Compare:
      The same regulator on another rail or another board shows the right voltages and the right resistances.
      Watch for:
      Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

    • IXD1602A1810R-Gprinted 1ADLDO regulator, IXYSLDO regulatorNot recordedNot recordedIXYS

      Printed 1AD on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

      What it is
      LDO regulator
      Maker
      IXYS
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Linear voltage regulator IC: LDO, 1.8V±20mV, 1A, +CE, soft start
      Source
      Published code list

      Is it dead?

      Voltage, board powered, black probe on ground. Then ohms with the power off.

      Working, it reads

      Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

      Dead, it reads

      • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
      • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
      • Power off, input to output near 0 Ω: shorted.
      On the board:
      An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
      Compare:
      The same regulator on another rail or another board shows the right voltages and the right resistances.
      Watch for:
      Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

    • NCP551SN15T1Gprinted LAOLDO regulatorLDO regulatorNot recordedNot recordedNot recorded

      Printed LAO on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

      What it is
      LDO regulator
      Maker
      Not recorded
      Package
      Not recorded
      Pins
      Not recorded
      Source
      Published code list

      Is it dead?

      Voltage, board powered, black probe on ground. Then ohms with the power off.

      Working, it reads

      Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

      Dead, it reads

      • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
      • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
      • Power off, input to output near 0 Ω: shorted.
      On the board:
      An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
      Compare:
      The same regulator on another rail or another board shows the right voltages and the right resistances.
      Watch for:
      Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

    • XC6129N21L7R-Gprinted LADVoltage supervisor, TorexVoltage supervisorNot recordedNot recordedTorex

      Printed LAD on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

      What it is
      Voltage supervisor
      Maker
      Torex
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Voltage detector IC: 2.1V±0.8%, +Reset ODO, Rel. Delay, Det. Delay
      Source
      Published code list

      Is it dead?

      Voltage with the board powered; ohms from each pin to ground with it off.

      Working, it reads

      Supply pin at its voltage and the output doing what the datasheet says. Readings between pins depend on the part.

      Dead, it reads

      • A pin near 0 Ω to ground or to the supply pin where an identical part does not read that: failed short.
      • Supply present, output stuck: failed, or its load has.
      On the board:
      A pin shorted to ground on the board can be anything on that net. Lift the pin to be sure.
      Compare:
      The surest reference is the same IC on a working board, measured pin by pin.
      Watch for:
      Its protection diodes can read like junctions between pins, even like a transistor. That proves nothing either way.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

    • XC6129N55L7R-Gprinted LA0Voltage supervisor, TorexVoltage supervisorNot recordedNot recordedTorex

      Printed LA0 on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

      What it is
      Voltage supervisor
      Maker
      Torex
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Voltage detector IC: 5.5V±0.8%, +Reset ODO, Rel. Delay, Det. Delay
      Source
      Published code list

      Is it dead?

      Voltage with the board powered; ohms from each pin to ground with it off.

      Working, it reads

      Supply pin at its voltage and the output doing what the datasheet says. Readings between pins depend on the part.

      Dead, it reads

      • A pin near 0 Ω to ground or to the supply pin where an identical part does not read that: failed short.
      • Supply present, output stuck: failed, or its load has.
      On the board:
      A pin shorted to ground on the board can be anything on that net. Lift the pin to be sure.
      Compare:
      The surest reference is the same IC on a working board, measured pin by pin.
      Watch for:
      Its protection diodes can read like junctions between pins, even like a transistor. That proves nothing either way.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

    • XC6219A311MRprinted LA0LDO regulator, TorexLDO regulatorNot recordedNot recordedTorex

      Printed LA0 on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

      What it is
      LDO regulator
      Maker
      Torex
      Package
      Not recorded
      Pins
      Not recorded
      Source
      Published code list

      Is it dead?

      Voltage, board powered, black probe on ground. Then ohms with the power off.

      Working, it reads

      Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

      Dead, it reads

      • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
      • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
      • Power off, input to output near 0 Ω: shorted.
      On the board:
      An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
      Compare:
      The same regulator on another rail or another board shows the right voltages and the right resistances.
      Watch for:
      Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

    • XC6219A311PRprinted LA0LDO regulator, TorexLDO regulatorNot recordedNot recordedTorex

      Printed LA0 on the part. Easy to misread as 1AO. Check that character with a loupe before you order anything.

      What it is
      LDO regulator
      Maker
      Torex
      Package
      Not recorded
      Pins
      Not recorded
      Source
      Published code list

      Is it dead?

      Voltage, board powered, black probe on ground. Then ohms with the power off.

      Working, it reads

      Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

      Dead, it reads

      • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
      • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
      • Power off, input to output near 0 Ω: shorted.
      On the board:
      An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
      Compare:
      The same regulator on another rail or another board shows the right voltages and the right resistances.
      Watch for:
      Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

12 more parts are not listed here. Type more of the code to narrow the list.

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One code, several parts

Marking codes are not unique. In the standard code book, 6H on a SOT-23 is an NPN transistor, a varicap, an N-channel JFET, two digital transistors, a 3.6 V voltage detector: six parts from five makers. So a search on WhatSMD (What SMD) shows the parts we hold under that code and under codes easily misread as it, with only the columns that tell them apart.

6Hon a SOT-23, in the code book
  • NPN transistor
  • Varicap
  • N-channel JFET
  • Digital transistor ×2
  • 3.6 V voltage detector

When more than one is left

Tap Help me choose. Up to 4 quick answers: whether the part has failed, then what separates the parts left. Those get ranked with the reasoning and a test that settles it. That uses one identification: 2 a month are free without an account, and 3 with a free account.

When you cannot read it

Tap the camera in the field. We read the characters, keep the ones we are unsure of, and search every reading. A photo too soft to read is turned back on your phone first; if it is the only one you can get, you can still send it.

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