SMD code search: identify a part by its marking

6 parts in SOT-323 are printed D6-

Not sure which one you have?

Answer up to 4 quick questions and these 33 parts are ranked, with a meter test that settles it. It works on a dead part too.

TMMBD4148CAWSOT-323Switching diode, 3 pins, Galaxy MicroelectronicsSwitching diode3 pinsGalaxy Microelectronics
What it is
Switching diode
Maker
Galaxy Microelectronics
Package
SOT-323
Pins
3
Details
0.2A，100V, Surface Mount Small Signal Switching Diodes
Source
Manufacturer 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
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.
Datasheetfor TMMBD4148CAW, opens in a new tab
2SA1687-6SOT-3233 pins, onsemiNot recorded3 pinsonsemi
What it is
Not recorded
Maker
onsemi
Package
SOT-323
Pins
3
Details
Si-pnp: GP, AF, 60V, 150mA, 150mW, B=200..400, 130MHz
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.
AP8821C-36GTSOT-323Voltage supervisor, 3 pins, Anwell SemiconductorVoltage supervisor3 pinsAnwell Semiconductor
What it is
Voltage supervisor
Maker
Anwell Semiconductor
Package
SOT-323
Pins
3
Details
Voltage detector IC: 3.6V±2%, -Reset PPO, H-free
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.
AP8821C-36PTSOT-323Voltage supervisor, 3 pins, Anwell SemiconductorVoltage supervisor3 pinsAnwell Semiconductor
What it is
Voltage supervisor
Maker
Anwell Semiconductor
Package
SOT-323
Pins
3
Details
Voltage detector IC: 3.6V±2%, -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.
BBY57-05WSOT-3233 pins, InfineonNot recorded3 pinsInfineon
What it is
Not recorded
Maker
Infineon
Package
SOT-323
Pins
3
Source
An older or alternative marking, from a 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.
Datasheetfor BBY57-05W, opens in a new tab
EC95808C36C1NSOT-323Voltage supervisor, 3 pins, E-CMOSVoltage supervisor3 pinsE-CMOS
What it is
Voltage supervisor
Maker
E-CMOS
Package
SOT-323
Pins
3
Details
Voltage detector IC: 3.6V±2%, -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.
27 more parts have no package on record. Nothing rules them out, so they stay.
- BFU730FRF transistor, 4 pins, NXPRF transistor4 pinsNXP
  What it is
  RF transistor
  Maker
  NXP
  Package
  Not recorded
  Pins
  4
  Details
  NPN wideband silicon germanium RF transistor
  Source
  Manufacturer datasheet
  Is it dead?
  Diode range, part lifted or its base leg off the pad.
  Working, it reads
  From the base, one probe colour 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.
  Datasheetfor BFU730F, opens in a new tab
- IMD6ADigital transistor (resistors built in), ROHMDigital transistor (resistors built in)Not recordedROHM
  What it is
  Digital transistor (resistors built in)
  Maker
  ROHM
  Package
  Not recorded
  Pins
  Not recorded
  Details
  General purpose (dual digital transistor)
  Source
  Manufacturer datasheet
  Is it dead?
  Ohms range, part lifted. The datasheet gives the built-in resistors: R1 in series with the base, R2 from base to emitter.
  Working, it reads
  Base to emitter reads about R1 plus R2 either way round, about 20 kΩ on a 10 k and 10 k part, give or take their wide tolerance. Collector to emitter reads open. A part with no R2 reads a junction behind R1 one way instead.
  Dead, it reads
  Collector to emitter the same both ways, near 0 Ω with a continuous beep: shorted.
  From the base, open or far above R1 plus R2: R1 has failed. Static damage shows here most often.
  Base to emitter near 0 Ω: failed short.
  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:
  The readings depend on the resistor values, so an identical part elsewhere on the board is the surest reference. Measure it the same way.
  Watch for:
  On the diode range a good part with 10 kΩ resistors reads open on every pair, so a good part looks dead there. Use the ohms range.
  A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
  Datasheetfor IMD6A, opens in a new tab
- NC7ST86L6Logic gate, onsemiLogic gateNot recordedonsemi
  What it is
  Logic gate
  Maker
  onsemi
  Package
  Not recorded
  Pins
  Not recorded
  Details
  TinyLogic HST 2-Input Exclusive-OR Gate
  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.
  Datasheetfor NC7ST86L6, opens in a new tab
- 2SA1687-7Sanyo ElectricNot recordedNot recordedSanyo Electric
  What it is
  Not recorded
  Maker
  Sanyo Electric
  Package
  Not recorded
  Pins
  Not recorded
  Details
  Si-pnp: GP, AF, 60V, 150mA, 150mW, B=300..600, 130MHz
  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.
- AP131-47TWAnachipNot recordedNot recordedAnachip
  What it is
  Not recorded
  Maker
  Anachip
  Package
  Not recorded
  Pins
  Not recorded
  Details
  VR-IC: LDO, CE, 4,7V±2%, 300mA
  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.
- AP8821C-36GIVoltage supervisor, Anwell SemiconductorVoltage supervisorNot recordedAnwell Semiconductor
  What it is
  Voltage supervisor
  Maker
  Anwell Semiconductor
  Package
  Not recorded
  Pins
  Not recorded
  Details
  Voltage detector IC: 3.6V±2%, -Reset PPO, H-free
  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.
- AP8821C-36GSVoltage supervisor, Anwell SemiconductorVoltage supervisorNot recordedAnwell Semiconductor
  What it is
  Voltage supervisor
  Maker
  Anwell Semiconductor
  Package
  Not recorded
  Pins
  Not recorded
  Details
  Voltage detector IC: 3.6V±2%, -Reset PPO, H-free
  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.
- AP8821C-36PIVoltage supervisor, Anwell SemiconductorVoltage supervisorNot recordedAnwell Semiconductor
  What it is
  Voltage supervisor
  Maker
  Anwell Semiconductor
  Package
  Not recorded
  Pins
  Not recorded
  Details
  Voltage detector IC: 3.6V±2%, -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.
- AP8821C-36PSVoltage supervisor, Anwell SemiconductorVoltage supervisorNot recordedAnwell Semiconductor
  What it is
  Voltage supervisor
  Maker
  Anwell Semiconductor
  Package
  Not recorded
  Pins
  Not recorded
  Details
  Voltage detector IC: 3.6V±2%, -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.
- BD45E272G-MVoltage supervisor, ROHMVoltage supervisorNot recordedROHM
  What it is
  Voltage supervisor
  Maker
  ROHM
  Package
  Not recorded
  Pins
  Not recorded
  Details
  Voltage detector IC: 2.7V±1%, -MR, -Reset ODO, Rdt=200ms
  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.
- CGY196RF amplifier (MMIC), 8 pins, InfineonRF amplifier (MMIC)8 pinsInfineon
  What it is
  RF amplifier (MMIC)
  Maker
  Infineon
  Package
  Not recorded
  Pins
  8
  Details
  Monolithic microwave IC: GaAs UHF multiband power amp. 2..6V, 0.8...3.5GHz (26dB)
  Source
  Published code list
  Is it dead?
  Voltage, board powered, on the output pin that the bias resistor or choke feeds.
  Working, it reads
  The output pin sits at the device voltage the datasheet gives, a few volts, below the supply.
  Dead, it reads
  Output pin at 0 V, or near 0 Ω to ground with the power off: shorted inside.
  Output pin at the full supply voltage: open inside, no current flowing.
  On the board:
  Measured on the board with power on; the bias network is part of the reading.
  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 figures depend on the part and its bias resistor. The datasheet gives both.
  A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
- EC95808C36C7IVoltage supervisor, E-CMOSVoltage supervisorNot recordedE-CMOS
  What it is
  Voltage supervisor
  Maker
  E-CMOS
  Package
  Not recorded
  Pins
  Not recorded
  Details
  Voltage detector IC: 3.6V±2%, -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.
- EC95808C36C7SVoltage supervisor, E-CMOSVoltage supervisorNot recordedE-CMOS
  What it is
  Voltage supervisor
  Maker
  E-CMOS
  Package
  Not recorded
  Pins
  Not recorded
  Details
  Voltage detector IC: 3.6V±2%, -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.
- IXD1233H17BNR-GLDO regulator, IXYSLDO regulatorNot recordedIXYS
  What it is
  LDO regulator
  Maker
  IXYS
  Package
  Not recorded
  Pins
  Not recorded
  Details
  Linear voltage regulator IC: LDO, 1.75V±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.
- NC7ST86LFairchild SemiconductorNot recordedNot recordedFairchild Semiconductor
  What it is
  Not recorded
  Maker
  Fairchild Semiconductor
  Package
  Not recorded
  Pins
  Not recorded
  Details
  CMOS logic IC: 2-input EXCLUSIVE-OR gate
  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.
- RKZ4.3B2KKZener diode, RenesasZener diodeNot recordedRenesas
  What it is
  Zener diode
  Maker
  Renesas
  Package
  Not recorded
  Pins
  Not recorded
  Details
  Zener diode: 4.15..4.34V, Izt=5mA, Zzt=130, 150mW
  Source
  Published code list
  Is it dead?
  Diode range for the forward check, part lifted, red probe on the anode. A bench supply for the Zener voltage.
  Working, it reads
  About 0.6 to 0.8 V forward and open in reverse on the diode range. Its Zener voltage shows only on a supply: feed it through a resistor that sets about 5 mA, cathode to positive, read quickly, and it should hold near its rated voltage.
  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, forward too: failed open.
  Holds well off its rated voltage on the supply test: drifted.
  A soft knee, or a voltage that creeps on the supply test: 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 meter's diode range stops at about 2 to 3 V, so almost every Zener reads open in reverse on it, good or bad; a 3 V meter may just show a 2.4 or 2.7 V part. Above about 3 V the meter cannot tell a Zener from a plain diode.
  A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
- RKZ4.3B2KLZener diode, RenesasZener diodeNot recordedRenesas
  What it is
  Zener diode
  Maker
  Renesas
  Package
  Not recorded
  Pins
  Not recorded
  Details
  Zener diode: 4.15..4.34V, Izt=5mA, Zzt=130, 100mW
  Source
  Published code list
  Is it dead?
  Diode range for the forward check, part lifted, red probe on the anode. A bench supply for the Zener voltage.
  Working, it reads
  About 0.6 to 0.8 V forward and open in reverse on the diode range. Its Zener voltage shows only on a supply: feed it through a resistor that sets about 5 mA, cathode to positive, read quickly, and it should hold near its rated voltage.
  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, forward too: failed open.
  Holds well off its rated voltage on the supply test: drifted.
  A soft knee, or a voltage that creeps on the supply test: 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 meter's diode range stops at about 2 to 3 V, so almost every Zener reads open in reverse on it, good or bad; a 3 V meter may just show a 2.4 or 2.7 V part. Above about 3 V the meter cannot tell a Zener from a plain diode.
  A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
- RN2907AFSToshibaNot recordedNot recordedToshiba
  What it is
  Not recorded
  Maker
  Toshiba
  Package
  Not recorded
  Pins
  Not recorded
  Details
  Si-pnp-Digi: Dual, Sw, 50V, 80mA, 50mW, R1/R2=10k/47k
  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.
- SN74LVC1G175DRYTexas InstrumentsNot recordedNot recordedTexas Instruments
  What it is
  Not recorded
  Maker
  Texas Instruments
  Package
  Not recorded
  Pins
  Not recorded
  Details
  CMOS logic IC: Positive edge-triggered D-type flip-flop with reset
  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.
- TCR2DG295LDO regulator, ToshibaLDO regulatorNot recordedToshiba
  What it is
  LDO regulator
  Maker
  Toshiba
  Package
  Not recorded
  Pins
  Not recorded
  Details
  Linear voltage regulator IC: LDO, 2.95V±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.
- XC6GC3602HRTorexNot recordedNot recordedTorex
  What it is
  Not recorded
  Maker
  Torex
  Package
  Not recorded
  Pins
  Not recorded
  Details
  CMOS-IC: Voltage Detector 3,6V, Reset Push-pull output
  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.
- XC6221A371NRLDO regulator, TorexLDO regulatorNot recordedTorex
  What it is
  LDO regulator
  Maker
  Torex
  Package
  Not recorded
  Pins
  Not recorded
  Details
  Linear voltage regulator IC: LDO, 3.7V±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.
- XC6221A3717RLDO regulator, TorexLDO regulatorNot recordedTorex
  What it is
  LDO regulator
  Maker
  Torex
  Package
  Not recorded
  Pins
  Not recorded
  Details
  Linear voltage regulator IC: LDO, 3.7V±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.
- XC6223C161NR-GLDO regulator, TorexLDO regulatorNot recordedTorex
  What it is
  LDO regulator
  Maker
  Torex
  Package
  Not recorded
  Pins
  Not recorded
  Details
  Linear voltage regulator IC: LDO, 1.6V±20mV, 300mA, +CE, PDR
  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.
- XC6223F16B9R-GLDO regulator, TorexLDO regulatorNot recordedTorex
  What it is
  LDO regulator
  Maker
  Torex
  Package
  Not recorded
  Pins
  Not recorded
  Details
  Linear voltage regulator IC: LDO, 1.65V±20mV, 300mA, +CE, CL, ICP
  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.
- XC6233H17BNR-GLDO regulator, TorexLDO regulatorNot recordedTorex
  What it is
  LDO regulator
  Maker
  Torex
  Package
  Not recorded
  Pins
  Not recorded
  Details
  Linear voltage regulator IC: LDO, 1.75V±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.
- XC9245A14C7R-GDC-DC converter, TorexDC-DC converterNot recordedTorex
  What it is
  DC-DC converter
  Maker
  Torex
  Package
  Not recorded
  Pins
  Not recorded
  Details
  DC/DC voltage converter IC: PWM/PFM st-dwn, 1.2MHz, 1.4V±2.0%, 400mA, +CE
  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.

174 more parts are printed with a code easy to misread as D6-: 16 in SOT-323, 158 with no package on record

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.

DTC144TU3printed 06SOT-323Digital transistor (NPN, resistors built in), 3 pins, ROHMDigital transistor (NPN, resistors built in)3 pinsROHM
Printed 06 on the part. Easy to misread as D6-. Check that character with a loupe before you order anything.
What it is
Digital transistor (NPN, resistors built in)
Maker
ROHM
Package
SOT-323
Pins
3
Source
Manufacturer datasheet
Is it dead?
Ohms range, part lifted. The datasheet gives the built-in resistors: R1 in series with the base, R2 from base to emitter.
Working, it reads
Base to emitter reads about R1 plus R2 either way round, about 20 kΩ on a 10 k and 10 k part, give or take their wide tolerance. Collector to emitter reads open. A part with no R2 reads a junction behind R1 one way instead.
Dead, it reads
Collector to emitter the same both ways, near 0 Ω with a continuous beep: shorted.
From the base, open or far above R1 plus R2: R1 has failed. Static damage shows here most often.
Base to emitter near 0 Ω: failed short.
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:
The readings depend on the resistor values, so an identical part elsewhere on the board is the surest reference. Measure it the same way.
Watch for:
On the diode range a good part with 10 kΩ resistors reads open on every pair, so a good part looks dead there. Use the ohms range.
A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
Datasheetfor DTC144TU3, opens in a new tab
DTC144TUAprinted 06SOT-323Digital transistor (NPN, resistors built in), 3 pins, JSCJDigital transistor (NPN, resistors built in)3 pinsJSCJ
Printed 06 on the part. Easy to misread as D6-. Check that character with a loupe before you order anything.
What it is
Digital transistor (NPN, resistors built in)
Maker
JSCJ
Package
SOT-323
Pins
3
Details
Digital transistor (bias resistors built in), NPN
Source
Manufacturer datasheet
Is it dead?
Ohms range, part lifted. The datasheet gives the built-in resistors: R1 in series with the base, R2 from base to emitter.
Working, it reads
Base to emitter reads about R1 plus R2 either way round, about 20 kΩ on a 10 k and 10 k part, give or take their wide tolerance. Collector to emitter reads open. A part with no R2 reads a junction behind R1 one way instead.
Dead, it reads
Collector to emitter the same both ways, near 0 Ω with a continuous beep: shorted.
From the base, open or far above R1 plus R2: R1 has failed. Static damage shows here most often.
Base to emitter near 0 Ω: failed short.
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:
The readings depend on the resistor values, so an identical part elsewhere on the board is the surest reference. Measure it the same way.
Watch for:
On the diode range a good part with 10 kΩ resistors reads open on every pair, so a good part looks dead there. Use the ohms range.
A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
Datasheetfor DTC144TUA, opens in a new tab
PDTC124EUprinted 06SOT-323Digital transistor (NPN, resistors built in), 3 pins, NexperiaDigital transistor (NPN, resistors built in)3 pinsNexperia
Printed 06 on the part. Easy to misread as D6-. Check that character with a loupe before you order anything.
What it is
Digital transistor (NPN, resistors built in)
Maker
Nexperia
Package
SOT-323
Pins
3
Details
50 V, 100 mA NPN resistor-equipped transistor; R1 = 22 kOhm, R2 = 22 kOhm
Source
Manufacturer datasheet
Is it dead?
Ohms range, part lifted. The datasheet gives the built-in resistors: R1 in series with the base, R2 from base to emitter.
Working, it reads
Base to emitter reads about R1 plus R2 either way round, about 20 kΩ on a 10 k and 10 k part, give or take their wide tolerance. Collector to emitter reads open. A part with no R2 reads a junction behind R1 one way instead.
Dead, it reads
Collector to emitter the same both ways, near 0 Ω with a continuous beep: shorted.
From the base, open or far above R1 plus R2: R1 has failed. Static damage shows here most often.
Base to emitter near 0 Ω: failed short.
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:
The readings depend on the resistor values, so an identical part elsewhere on the board is the surest reference. Measure it the same way.
Watch for:
On the diode range a good part with 10 kΩ resistors reads open on every pair, so a good part looks dead there. Use the ohms range.
A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
Datasheetfor PDTC124EU, opens in a new tab
SM1406NSSprinted 06SOT-323N-channel MOSFET, 3 pins, Sinopower SemiconductorN-channel MOSFET3 pinsSinopower Semiconductor
Printed 06 on the part. Easy to misread as D6-. Check that character with a loupe before you order anything.
What it is
N-channel MOSFET
Maker
Sinopower Semiconductor
Package
SOT-323
Pins
3
Details
30 V, 1 A N-channel MOSFET
Source
Manufacturer datasheet
Is it dead?
Diode range, part lifted. Test drain to source first, then short gate to source and test again.
Working, it reads
Red probe on the source, black on the drain: about 0.4 to 0.9 V, the body diode. Open the other way. The gate reads open to both other pins, both ways.
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. Often all three pins end up shorted together.
No body diode at all: failed open.
On the board
the gate usually has a resistor to the source, so gate to source reads that resistor, which is not a fault. A drain short can be the load. 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.
Datasheetfor SM1406NSS, opens in a new tab
2SC4117-GRprinted DGSOT-323NPN transistor, 3 pins, ToshibaNPN transistor3 pinsToshiba
Printed DG on the part. Easy to misread as D6-. Check that character with a loupe before you order anything.
What it is
NPN transistor
Maker
Toshiba
Package
SOT-323
Pins
3
Details
Si-npn: AF-Amp, 120V, 100mA, 100mW, 100MHz, B=200..400
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.
2SC4117GRprinted DGSOT-3233 pins, ToshibaNot recorded3 pinsToshiba
Printed DG on the part. Easy to misread as D6-. Check that character with a loupe before you order anything.
What it is
Not recorded
Maker
Toshiba
Package
SOT-323
Pins
3
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.
2SC5343U-Gprinted DGSOT-323NPN transistor, 3 pins, AUK SemiconductorNPN transistor3 pinsAUK Semiconductor
Printed DG on the part. Easy to misread as D6-. Check that character with a loupe before you order anything.
What it is
NPN transistor
Maker
AUK Semiconductor
Package
SOT-323
Pins
3
Details
NPN transistor: GP, 60V, 150mA, 200mW, >80MHz, B=200..400
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.
AP8822C-46GTprinted 06SOT-323Voltage supervisor, 3 pins, Anwell SemiconductorVoltage supervisor3 pinsAnwell Semiconductor
Printed 06 on the part. Easy to misread as D6-. Check that character with a loupe before you order anything.
What it is
Voltage supervisor
Maker
Anwell Semiconductor
Package
SOT-323
Pins
3
Details
Voltage detector IC: 4.6V±2%, -Reset PPO, Rdt=200ms, H-free
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.
AP8822C-46PTprinted 06SOT-323Voltage supervisor, 3 pins, Anwell SemiconductorVoltage supervisor3 pinsAnwell Semiconductor
Printed 06 on the part. Easy to misread as D6-. Check that character with a loupe before you order anything.
What it is
Voltage supervisor
Maker
Anwell Semiconductor
Package
SOT-323
Pins
3
Details
Voltage detector IC: 4.6V±2%, -Reset PPO, Rdt=200ms
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.
BRC124ECMprinted DGSOT-323Digital transistor (NPN, resistors built in), 3 pins, RenesasDigital transistor (NPN, resistors built in)3 pinsRenesas
Printed DG on the part. Easy to misread as D6-. Check that character with a loupe before you order anything.
What it is
Digital transistor (NPN, resistors built in)
Maker
Renesas
Package
SOT-323
Pins
3
Details
NPN transistor: Sw, 50V, 100mA, 150mW, R1/R2=22k/22k
Source
Published code list
Is it dead?
Ohms range, part lifted. The datasheet gives the built-in resistors: R1 in series with the base, R2 from base to emitter.
Working, it reads
Base to emitter reads about R1 plus R2 either way round, about 20 kΩ on a 10 k and 10 k part, give or take their wide tolerance. Collector to emitter reads open. A part with no R2 reads a junction behind R1 one way instead.
Dead, it reads
Collector to emitter the same both ways, near 0 Ω with a continuous beep: shorted.
From the base, open or far above R1 plus R2: R1 has failed. Static damage shows here most often.
Base to emitter near 0 Ω: failed short.
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:
The readings depend on the resistor values, so an identical part elsewhere on the board is the surest reference. Measure it the same way.
Watch for:
On the diode range a good part with 10 kΩ resistors reads open on every pair, so a good part looks dead there. Use the ohms range.
A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
EC95810C46C1Nprinted 06SOT-323Voltage supervisor, 3 pins, E-CMOSVoltage supervisor3 pinsE-CMOS
Printed 06 on the part. Easy to misread as D6-. Check that character with a loupe before you order anything.
What it is
Voltage supervisor
Maker
E-CMOS
Package
SOT-323
Pins
3
Details
Voltage detector IC: 4.6V±2%, -Reset PPO, Rdt=200ms
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.
MCP121T-195I/LBprinted DGSOT-3233 pins, MicrochipNot recorded3 pinsMicrochip
Printed DG on the part. Easy to misread as D6-. Check that character with a loupe before you order anything.
What it is
Not recorded
Maker
Microchip
Package
SOT-323
Pins
3
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.
PMSS3906printed -06SOT-323PNP transistor, 3 pinsPNP transistor3 pinsNot recorded
Printed -06 on the part. Easy to misread as D6-. Check that character with a loupe before you order anything.
What it is
PNP transistor
Maker
Not recorded
Package
SOT-323
Pins
3
Details
PNP switching transistor
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.
Datasheetfor PMSS3906, opens in a new tab
RN1323Aprinted QCSOT-323Digital transistor (NPN, resistors built in), 3 pins, ToshibaDigital transistor (NPN, resistors built in)3 pinsToshiba
Printed QC on the part. Easy to misread as D6-. Check that character with a loupe before you order anything.
What it is
Digital transistor (NPN, resistors built in)
Maker
Toshiba
Package
SOT-323
Pins
3
Details
Si-npn-Digi: Mute, 15V, 500mA, 300mW, R1/R2=4k7/4k7
Source
Published code list
Is it dead?
Ohms range, part lifted. The datasheet gives the built-in resistors: R1 in series with the base, R2 from base to emitter.
Working, it reads
Base to emitter reads about R1 plus R2 either way round, about 20 kΩ on a 10 k and 10 k part, give or take their wide tolerance. Collector to emitter reads open. A part with no R2 reads a junction behind R1 one way instead.
Dead, it reads
Collector to emitter the same both ways, near 0 Ω with a continuous beep: shorted.
From the base, open or far above R1 plus R2: R1 has failed. Static damage shows here most often.
Base to emitter near 0 Ω: failed short.
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:
The readings depend on the resistor values, so an identical part elsewhere on the board is the surest reference. Measure it the same way.
Watch for:
On the diode range a good part with 10 kΩ resistors reads open on every pair, so a good part looks dead there. Use the ohms range.
A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
RN1327Aprinted QGSOT-323Digital transistor (NPN, resistors built in), 3 pins, ToshibaDigital transistor (NPN, resistors built in)3 pinsToshiba
Printed QG on the part. Easy to misread as D6-. Check that character with a loupe before you order anything.
What it is
Digital transistor (NPN, resistors built in)
Maker
Toshiba
Package
SOT-323
Pins
3
Details
Si-npn-Digi: Mute, 15V, 500mA, 300mW, R1/R2=2k2/10k
Source
Published code list
Is it dead?
Ohms range, part lifted. The datasheet gives the built-in resistors: R1 in series with the base, R2 from base to emitter.
Working, it reads
Base to emitter reads about R1 plus R2 either way round, about 20 kΩ on a 10 k and 10 k part, give or take their wide tolerance. Collector to emitter reads open. A part with no R2 reads a junction behind R1 one way instead.
Dead, it reads
Collector to emitter the same both ways, near 0 Ω with a continuous beep: shorted.
From the base, open or far above R1 plus R2: R1 has failed. Static damage shows here most often.
Base to emitter near 0 Ω: failed short.
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:
The readings depend on the resistor values, so an identical part elsewhere on the board is the surest reference. Measure it the same way.
Watch for:
On the diode range a good part with 10 kΩ resistors reads open on every pair, so a good part looks dead there. Use the ohms range.
A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
SSM3K04FUprinted DCSOT-3233 pins, ToshibaNot recorded3 pinsToshiba
Printed DC on the part. Easy to misread as D6-. Check that character with a loupe before you order anything.
What it is
Not recorded
Maker
Toshiba
Package
SOT-323
Pins
3
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.
1 more part has no package on record. Nothing rules it out, so it stays.
- 74LVC2G17XUDL6Gprinted 0CLogic gate, 6 pins, SG MicroLogic gate6 pinsSG Micro
  Printed 0C on the part. Easy to misread as D6-. Check that character with a loupe before you order anything.
  What it is
  Logic gate
  Maker
  SG Micro
  Package
  Not recorded
  Pins
  6
  Details
  Dual Buffer with Schmitt-Trigger
  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.
  Datasheetfor 74LVC2G17XUDL6G, opens in a new tab

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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

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SMD code search: identify a part by its marking

What’s printed on it?

6 parts in SOT-323 are printed D6-

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Printed with a code easy to misread

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One code, several parts

When more than one is left

When you cannot read it

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