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12 parts are printed AR.

Not sure which one you have?

Answer up to 4 quick questions and these 12 parts are ranked, with a meter test that settles it. It works on a dead part too.

  • AO3422SOT-23MOSFET, 3 pins, Alpha & Omega Semiconductor
    What it is
    MOSFET
    Maker
    Alpha & Omega Semiconductor
    Package
    SOT-23
    Pins
    3
    Details
    Medium-voltage (40-400 V) MOSFET
    Source
    From the manufacturer's datasheet

    Is it dead?

    Diode range, part lifted. Test drain to source first, then short gate to source and test again.

    Working, it reads

    One way between drain and source reads about 0.4 to 0.9 V, the body diode, and the other way open. The gate reads open to both other pins.

    Dead, it reads

    • Drain to source the same both ways, near 0 V with a continuous beep, and still so after shorting gate to source: shorted. The classic failure.
    • The gate reads low to source or drain: gate shorted.
    • No body diode at all: failed open.
    On the board:
    On the board the gate usually has a resistor to the source, which reads as that resistor and is not a fault. Lift a leg to be sure.
    Compare:
    If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.
    Watch for:
    The diode range can charge the gate enough to turn the part on, and then drain to source reads near 0 both ways on a good part. Short gate to source and test again before you condemn it.

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

  • AO3422LSOT-23MOSFET, 3 pins, Alpha & Omega Semiconductor
    What it is
    MOSFET
    Maker
    Alpha & Omega Semiconductor
    Package
    SOT-23
    Pins
    3
    Details
    Medium-voltage (40-400 V) MOSFET
    Source
    From the manufacturer's datasheet

    Is it dead?

    Diode range, part lifted. Test drain to source first, then short gate to source and test again.

    Working, it reads

    One way between drain and source reads about 0.4 to 0.9 V, the body diode, and the other way open. The gate reads open to both other pins.

    Dead, it reads

    • Drain to source the same both ways, near 0 V with a continuous beep, and still so after shorting gate to source: shorted. The classic failure.
    • The gate reads low to source or drain: gate shorted.
    • No body diode at all: failed open.
    On the board:
    On the board the gate usually has a resistor to the source, which reads as that resistor and is not a fault. Lift a leg to be sure.
    Compare:
    If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.
    Watch for:
    The diode range can charge the gate enough to turn the part on, and then drain to source reads near 0 both ways on a good part. Short gate to source and test again before you condemn it.

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

  • BAS16JSOD-323Switching diode, 2 pins, Nexperia
    What it is
    Switching diode
    Maker
    Nexperia
    Package
    SOD-323
    Pins
    2
    Details
    High-speed switching diode, single
    Source
    From the manufacturer's datasheet

    Is it dead?

    Diode range, part lifted or one leg off the pad. Red probe on the anode.

    Working, it reads

    About 0.5 to 0.8 V anode to cathode, and open the other way. Small switching diodes read about 0.6 to 0.7 V; large rectifiers can read a little lower.

    Dead, it reads

    • The same reading both ways round, near 0 V with a continuous beep or the same middling value: shorted.
    • Open both ways: failed open.
    • A reading the wrong way round as well: leaky.
    On the board:
    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 three-pin body can hold two diodes. With a common pin they read two junctions from that pin, just like a transistor; in series they read two drops end to end. Test each pair the datasheet names.

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

  • PJGBLC08CSOD-323ESD protection diode, 2 pins, Panjit
    What it is
    ESD protection diode
    Maker
    Panjit
    Package
    SOD-323
    Pins
    2
    Source
    From the manufacturer's datasheet

    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:
    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.

  • PJGBLC08C-AUSOD-323ESD protection diode, 2 pins, Panjit
    What it is
    ESD protection diode
    Maker
    Panjit
    Package
    SOD-323
    Pins
    2
    Source
    From the manufacturer's datasheet

    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:
    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.

  • SMAJ8.0ASMATVS diode, 2 pins, Vishay
    What it is
    TVS diode
    Maker
    Vishay
    Package
    SMA
    Pins
    2
    Details
    400 W TVS diode, unidirectional
    Source
    From the manufacturer's datasheet

    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:
    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.

  • SMBJ8.0CASMBTVS diode, 2 pins, Vishay
    What it is
    TVS diode
    Maker
    Vishay
    Package
    SMB
    Pins
    2
    Details
    600 W TVS diode, bidirectional
    Source
    From the manufacturer's datasheet

    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:
    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.

  • SMF8V0ASOD-123FESD protection diode, 2 pins, Vishay
    What it is
    ESD protection diode
    Maker
    Vishay
    Package
    SOD-123F
    Pins
    2
    Source
    From the manufacturer's datasheet

    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:
    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.

  • 4 more parts have no package on record
    • MSMP8.0ATVS diode, Vishay
      What it is
      TVS diode
      Maker
      Vishay
      Package
      Not recorded
      Pins
      Not recorded
      Details
      150 W TVS diode, unidirectional
      Source
      From the manufacturer's datasheet

      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:
      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.

    • SMBG8.0ATVS diode, Vishay
      What it is
      TVS diode
      Maker
      Vishay
      Package
      Not recorded
      Pins
      Not recorded
      Details
      600 W TVS diode, unidirectional
      Source
      From the manufacturer's datasheet

      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:
      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.

    • SMP8.0ATVS diode, Vishay
      What it is
      TVS diode
      Maker
      Vishay
      Package
      Not recorded
      Pins
      Not recorded
      Details
      400 W TVS diode, unidirectional
      Source
      From the manufacturer's datasheet

      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:
      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.

    • VESD05A5A-HSFESD protection diode, Vishay
      What it is
      ESD protection diode
      Maker
      Vishay
      Package
      Not recorded
      Pins
      Not recorded
      Details
      5-Line ESD Protection Diode Array in LLP75
      Source
      From the manufacturer's datasheet

      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:
      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.

12 more parts have codes that begin with AR

Codes that begin with AR

For a marking with its end worn or burnt off. Each one shows its full printed code.

  • BSR43printed AR4SOT-89NPN transistor, 3 pins, JSCJ

    Printed AR4. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

    What it is
    NPN transistor
    Maker
    JSCJ
    Package
    SOT-89
    Pins
    3
    Details
    Bipolar transistor, NPN, 80 V, 1 A
    Source
    From the manufacturer's 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:
    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.

  • LM7321QMFprinted AR8ASOT-23-5Operational amplifier, 5 pins, Texas Instruments

    Printed AR8A. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

    What it is
    Operational amplifier
    Maker
    Texas Instruments
    Package
    SOT-23-5
    Pins
    5
    Details
    Single and LM7322x Dual Rail-to-Rail Input and Output ±15V, High-Output Current and Unlimited Capacitive Load...
    Source
    From the manufacturer's 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.

  • LM7321QMFEprinted AR8ASOT-23-5Operational amplifier, 5 pins, Texas Instruments

    Printed AR8A. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

    What it is
    Operational amplifier
    Maker
    Texas Instruments
    Package
    SOT-23-5
    Pins
    5
    Details
    Single and LM7322x Dual Rail-to-Rail Input and Output ±15V, High-Output Current and Unlimited Capacitive Load...
    Source
    From the manufacturer's 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.

  • LM7321QMFXprinted AR8ASOT-23-5Operational amplifier, 5 pins, Texas Instruments

    Printed AR8A. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

    What it is
    Operational amplifier
    Maker
    Texas Instruments
    Package
    SOT-23-5
    Pins
    5
    Details
    Single and LM7322x Dual Rail-to-Rail Input and Output ±15V, High-Output Current and Unlimited Capacitive Load...
    Source
    From the manufacturer's 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.

  • P4SMA11Aprinted ARJSMATVS diode, 2 pins, Taiwan Semiconductor

    Printed ARJ. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

    What it is
    TVS diode
    Maker
    Taiwan Semiconductor
    Package
    SMA
    Pins
    2
    Source
    From the manufacturer's datasheet

    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:
    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.

  • TPS71501DCKprinted ARBSOT-353LDO regulator, 5 pins, Texas Instruments

    Printed ARB. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

    What it is
    LDO regulator
    Maker
    Texas Instruments
    Package
    SOT-353
    Pins
    5
    Details
    50-mA, 24-V, 3.2-μA Quiescent Current, Low-Dropout Linear Regulator
    Source
    From the manufacturer's 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.

  • TPS71518DCKprinted ARDSOT-353LDO regulator, 5 pins, Texas Instruments

    Printed ARD. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

    What it is
    LDO regulator
    Maker
    Texas Instruments
    Package
    SOT-353
    Pins
    5
    Details
    50-mA, 24-V, 3.2-μA Quiescent Current, Low-Dropout Linear Regulator
    Source
    From the manufacturer's 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.

  • TPSMA11Aprinted ARPSMATVS diode, 2 pins, Vishay

    Printed ARP. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

    What it is
    TVS diode
    Maker
    Vishay
    Package
    SMA
    Pins
    2
    Details
    400 W TVS diode, unidirectional
    Source
    From the manufacturer's datasheet

    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:
    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.

  • 4 more parts have no package on record
    • TA6F11Aprinted ARPTVS diode, Vishay

      Printed ARP. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

      What it is
      TVS diode
      Maker
      Vishay
      Package
      Not recorded
      Pins
      Not recorded
      Details
      600 W TVS diode, unidirectional
      Source
      From the manufacturer's datasheet

      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:
      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.

    • TA6L11Aprinted ARLTVS diode, Vishay

      Printed ARL. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

      What it is
      TVS diode
      Maker
      Vishay
      Package
      Not recorded
      Pins
      Not recorded
      Details
      600 W TVS diode, unidirectional
      Source
      From the manufacturer's datasheet

      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:
      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.

    • TPSMA6L8.0Aprinted ARATVS diode, Diotec

      Printed ARA. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

      What it is
      TVS diode
      Maker
      Diotec
      Package
      Not recorded
      Pins
      Not recorded
      Details
      SMD Transient Voltage Suppressor Diodes
      Source
      From the manufacturer's datasheet

      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:
      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.

    • TPSMP11Aprinted ARPTVS diode, Vishay

      Printed ARP. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

      What it is
      TVS diode
      Maker
      Vishay
      Package
      Not recorded
      Pins
      Not recorded
      Details
      400 W TVS diode, unidirectional
      Source
      From the manufacturer's datasheet

      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:
      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.

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 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.