SMD code search: identify a part by its marking

2 parts are printed GUI

Not sure which one you have?

Answer up to 4 quick questions and these 2 parts are ranked, with a meter test that settles it. It works on a dead part too.

2 pins. What differs:

SMCJ130ASMCTVS diode, SGS-Thomson MicroelectronicsTVS diodeSMCSGS-Thomson Microelectronics
What it is
TVS diode
Maker
SGS-Thomson Microelectronics
Package
SMC
Pins
2
Source
Published code list
Is it dead?
Diode range, from the protected line to ground, part lifted if you can.
Working, it reads
A one-way part reads about 0.6 to 0.8 V forward and open in reverse. A two-way part reads open both ways. Arrays with several lines read as the datasheet's diagram draws them.
Dead, it reads
From the line to ground, the same reading both ways, near 0 V with a continuous beep: shorted.
A reading both ways on a one-way part: leaky.
A one-way part open both ways: failed open.
On the board
, a line reading shorted to ground can be this part or anything else on that line. Lift it: if the short goes with it, it has failed.
Compare:
The same part on the next line or connector pin is the healthy reading to compare with.
Watch for:
A two-way part reads open both ways when it is good, exactly like one that has failed open. The meter cannot tell them apart; an identical part on the next line can.
A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
Datasheetfor SMCJ130A, opens in a new tab
1 more part has no package on record
- SMCJ130A-TRSTMicroelectronicsNot recordedNot recordedSTMicroelectronics
  What it is
  Not recorded
  Maker
  STMicroelectronics
  Package
  Not recorded
  Pins
  2
  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.

40 more parts are printed with a code easy to misread as GUI

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.

BCX19printed GU1SOT-23NPN transistor, 3 pins, ROHMNPN transistorSOT-233 pinsROHM
Printed GU1 on the part. Easy to misread as GUI. Check that character with a loupe before you order anything.
What it is
NPN transistor
Maker
ROHM
Package
SOT-23
Pins
3
Details
45V, 0.5A, General Purpose NPN Bipolar Transistor
Source
Manufacturer datasheet
Is it dead?
Diode range, part lifted or its base leg off the pad.
Working, it reads
Red probe on the base reads about 0.6 to 0.75 V to the emitter and to the collector, and open the other way round. Collector to emitter reads open both ways.
Dead, it reads
Collector to emitter the same both ways, near 0 V with a continuous beep: shorted. The commonest failure.
The base the same both ways to another pin, near 0 V or a middling value: a shorted junction.
Only one junction reads, or none: a junction has failed open. It then looks like a diode.
A reading the wrong way round, where it should be open: leaky.
On the board
this is a first look only: the meter reads every path between those pins, and a short can be a neighbour. Lift one leg before you condemn it.
Compare:
If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.
Watch for:
A pair of diodes with a common pin reads just like a transistor, and some transistors carry a built-in diode or resistor. The datasheet says which.
A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
Datasheetfor BCX19, opens in a new tab
BZT52B16printed 6U1SOD-123FZener diode, 2 pins, DiotecZener diodeSOD-123F2 pinsDiotec
Printed 6U1 on the part. Easy to misread as GUI. Check that character with a loupe before you order anything.
What it is
Zener diode
Maker
Diotec
Package
SOD-123F
Pins
2
Source
Manufacturer datasheet
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.
Datasheetfor BZT52B16, opens in a new tab
CHDTA114GUGPprinted GU1SOT-323Digital transistor (PNP, resistors built in), 3 pins, ChenmkoDigital transistor (PNP, resistors built in)SOT-3233 pinsChenmko
Printed GU1 on the part. Easy to misread as GUI. Check that character with a loupe before you order anything.
What it is
Digital transistor (PNP, resistors built in)
Maker
Chenmko
Package
SOT-323
Pins
3
Details
PNP Digital Silicon Transistor, 50 V, 100 mA
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 CHDTA114GUGP, opens in a new tab
MM1ZB16printed 6U1SOD-123FZener diode, 2 pins, Good-ArkZener diodeSOD-123F2 pinsGood-Ark
Printed 6U1 on the part. Easy to misread as GUI. Check that character with a loupe before you order anything.
What it is
Zener diode
Maker
Good-Ark
Package
SOD-123F
Pins
2
Details
Zener diode, VZ 16 V, 0.5 W
Source
Manufacturer datasheet
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.
Datasheetfor MM1ZB16, opens in a new tab
3T150BLCprinted GULSMB2 pins, Lucky ForestNot recordedSMB2 pinsLucky Forest
Printed GUL on the part. Easy to misread as GUI. Check that character with a loupe before you order anything.
What it is
Not recorded
Maker
Lucky Forest
Package
SMB
Pins
2
Details
Thyristor surge protector: Vdrm=140V, Vs=180V, Ipp=2.2A(1ms), 40pF
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.
CHDTA114GUPTprinted GU1SOT-323Digital transistor (PNP, resistors built in), 3 pins, Chenmko EnterpriseDigital transistor (PNP, resistors built in)SOT-3233 pinsChenmko Enterprise
Printed GU1 on the part. Easy to misread as GUI. Check that character with a loupe before you order anything.
What it is
Digital transistor (PNP, resistors built in)
Maker
Chenmko Enterprise
Package
SOT-323
Pins
3
Details
PNP transistor: Sw, 50V, 100mA, 250MHz, R2=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.
ELM991013Bprinted 6U1SOT-23-5LDO regulator, 5 pins, ELM TechnologyLDO regulatorSOT-23-55 pinsELM Technology
Printed 6U1 on the part. Easy to misread as GUI. Check that character with a loupe before you order anything.
What it is
LDO regulator
Maker
ELM Technology
Package
SOT-23-5
Pins
5
Details
Linear voltage regulator IC: LDO, 10.1V±2%, 300mA, +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.
ELM991213Bprinted 6ULSOT-23-5LDO regulator, 5 pins, ELM TechnologyLDO regulatorSOT-23-55 pinsELM Technology
Printed 6UL on the part. Easy to misread as GUI. Check that character with a loupe before you order anything.
What it is
LDO regulator
Maker
ELM Technology
Package
SOT-23-5
Pins
5
Details
Linear voltage regulator IC: LDO, 12.1V±2%, 300mA, +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.
IXD3235G0LDER-Gprinted CULUSP-6CDC-DC converter, 6 pins, IXYSDC-DC converterUSP-6C6 pinsIXYS
Printed CUL on the part. Easy to misread as GUI. Check that character with a loupe before you order anything.
What it is
DC-DC converter
Maker
IXYS
Package
USP-6C
Pins
6
Details
DC/DC voltage converter IC: PWM, st-dwn, 0.85V±2%, 600mA, 3MHz, Vin>1.8V, HSST, CL
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.
IXD3235G0LDMR-Gprinted CULSOT-23-5DC-DC converter, 5 pins, IXYSDC-DC converterSOT-23-55 pinsIXYS
Printed CUL on the part. Easy to misread as GUI. Check that character with a loupe before you order anything.
What it is
DC-DC converter
Maker
IXYS
Package
SOT-23-5
Pins
5
Details
DC/DC voltage converter IC: PWM, st-dwn, 0.85V±2%, 600mA, 3MHz, Vin>1.8V, HSST, CL
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.
IXD3237E0LDER-Gprinted 6ULUSP-6CDC-DC converter, 6 pins, IXYSDC-DC converterUSP-6C6 pinsIXYS
Printed 6UL on the part. Easy to misread as GUI. Check that character with a loupe before you order anything.
What it is
DC-DC converter
Maker
IXYS
Package
USP-6C
Pins
6
Details
DC/DC voltage converter IC: PWM-PWM/PFM, st-dwn, 0.85V±2%, 600mA, 3MHz, Vin>1.8V, LSST, CL
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.
IXD3237E0LDMR-Gprinted 6ULSOT-23-5DC-DC converter, 5 pins, IXYSDC-DC converterSOT-23-55 pinsIXYS
Printed 6UL on the part. Easy to misread as GUI. Check that character with a loupe before you order anything.
What it is
DC-DC converter
Maker
IXYS
Package
SOT-23-5
Pins
5
Details
DC/DC voltage converter IC: PWM-PWM/PFM, st-dwn, 0.85V±2%, 600mA, 3MHz, Vin>1.8V, LSST, CL
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.
IXD5127N45JMRprinted 6ULSOT-23-5Voltage supervisor, 5 pins, IXYSVoltage supervisorSOT-23-55 pinsIXYS
Printed 6UL on the part. Easy to misread as GUI. Check that character with a loupe before you order anything.
What it is
Voltage supervisor
Maker
IXYS
Package
SOT-23-5
Pins
5
Details
Voltage detector IC: 4.5V±0.8%, +Reset ODO, -MR, Rdt=400ms
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.
MM1ZB16Hprinted 6U1SOD-123Zener diode, 2 pins, Zowie TechnologyZener diodeSOD-1232 pinsZowie Technology
Printed 6U1 on the part. Easy to misread as GUI. Check that character with a loupe before you order anything.
What it is
Zener diode
Maker
Zowie Technology
Package
SOD-123
Pins
2
Details
Zener diode: 15.68..16.32V, Izt=5mA, Zzt=40, 500mW
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.
R3120N024Aprinted CU1SOT-23-5Voltage supervisor, 5 pins, RicohVoltage supervisorSOT-23-55 pinsRicoh
Printed CU1 on the part. Easy to misread as GUI. Check that character with a loupe before you order anything.
What it is
Voltage supervisor
Maker
Ricoh
Package
SOT-23-5
Pins
5
Details
Voltage detector IC: 2.4V±1.5%, -Reset ODO
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.
S-817A19ANB-CUIT2printed CUISOT-3434 pins, ABLICNot recordedSOT-3434 pinsABLIC
Printed CUI on the part. Easy to misread as GUI. Check that character with a loupe before you order anything.
What it is
Not recorded
Maker
ABLIC
Package
SOT-343
Pins
4
Details
equivalent [1.9V LDO]
Source
Published code list
Is it dead?
Voltage, board powered, black probe on ground. Then ohms with the power off.
Working, it reads
Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.
Dead, it reads
Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
Power off, input to output near 0 Ω: shorted.
On the board:
An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
Compare:
The same regulator on another rail or another board shows the right voltages and the right resistances.
Watch for:
Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.
A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
S-817A19ANB-CUIT2Gprinted CUISOT-3434 pins, Seiko InstrumentsNot recordedSOT-3434 pinsSeiko Instruments
Printed CUI on the part. Easy to misread as GUI. Check that character with a loupe before you order anything.
What it is
Not recorded
Maker
Seiko Instruments
Package
SOT-343
Pins
4
Details
Linear voltage regulator IC: 1.9V±2%, 50mA
Source
Published code list
Is it dead?
Voltage, board powered, black probe on ground. Then ohms with the power off.
Working, it reads
Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.
Dead, it reads
Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
Power off, input to output near 0 Ω: shorted.
On the board:
An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
Compare:
The same regulator on another rail or another board shows the right voltages and the right resistances.
Watch for:
Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.
A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
S-817A22ANB-CULT2printed CULSOT-3434 pins, ABLICNot recordedSOT-3434 pinsABLIC
Printed CUL on the part. Easy to misread as GUI. Check that character with a loupe before you order anything.
What it is
Not recorded
Maker
ABLIC
Package
SOT-343
Pins
4
Details
equivalent [2.2V LDO]
Source
Published code list
Is it dead?
Voltage, board powered, black probe on ground. Then ohms with the power off.
Working, it reads
Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.
Dead, it reads
Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
Power off, input to output near 0 Ω: shorted.
On the board:
An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
Compare:
The same regulator on another rail or another board shows the right voltages and the right resistances.
Watch for:
Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.
A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
S-817A22ANB-CULTFGprinted CULSOT-3434 pins, Seiko InstrumentsNot recordedSOT-3434 pinsSeiko Instruments
Printed CUL on the part. Easy to misread as GUI. Check that character with a loupe before you order anything.
What it is
Not recorded
Maker
Seiko Instruments
Package
SOT-343
Pins
4
Details
Linear voltage regulator IC: 2.2V±2%, 50mA
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.
SMCJ154Aprinted GULSMC2 pins, SGS-Thomson MicroelectronicsNot recordedSMC2 pinsSGS-Thomson Microelectronics
Printed GUL on the part. Easy to misread as GUI. Check that character with a loupe before you order anything.
What it is
Not recorded
Maker
SGS-Thomson Microelectronics
Package
SMC
Pins
2
Details
TVS: 154V, 6.1A, 1500W (1ms)
Source
Published code list
Is it dead?
Diode range, from the protected line to ground, part lifted if you can.
Working, it reads
A one-way part reads about 0.6 to 0.8 V forward and open in reverse. A two-way part reads open both ways. Arrays with several lines read as the datasheet's diagram draws them.
Dead, it reads
From the line to ground, the same reading both ways, near 0 V with a continuous beep: shorted.
A reading both ways on a one-way part: leaky.
A one-way part open both ways: failed open.
On the board
, a line reading shorted to ground can be this part or anything else on that line. Lift it: if the short goes with it, it has failed.
Compare:
The same part on the next line or connector pin is the healthy reading to compare with.
Watch for:
A two-way part reads open both ways when it is good, exactly like one that has failed open. The meter cannot tell them apart; an identical part on the next line can.
A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
XC6127N45JMRprinted 6ULSOT-23-5Voltage supervisor, 5 pins, TorexVoltage supervisorSOT-23-55 pinsTorex
Printed 6UL on the part. Easy to misread as GUI. Check that character with a loupe before you order anything.
What it is
Voltage supervisor
Maker
Torex
Package
SOT-23-5
Pins
5
Details
Voltage detector IC: 4.5V±0.8%, +Reset ODO, -MR, Rdt=400ms
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.
XC9235G0LDER-Gprinted CULUSP-6CDC-DC converter, 6 pins, TorexDC-DC converterUSP-6C6 pinsTorex
Printed CUL on the part. Easy to misread as GUI. Check that character with a loupe before you order anything.
What it is
DC-DC converter
Maker
Torex
Package
USP-6C
Pins
6
Details
DC/DC voltage converter IC: PWM, st-dwn, 0.85V±2%, 600mA, 3MHz, Vin>1.8V, HSST, CL
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.
XC9235G0LDMR-Gprinted CULSOT-23-5DC-DC converter, 5 pins, TorexDC-DC converterSOT-23-55 pinsTorex
Printed CUL on the part. Easy to misread as GUI. Check that character with a loupe before you order anything.
What it is
DC-DC converter
Maker
Torex
Package
SOT-23-5
Pins
5
Details
DC/DC voltage converter IC: PWM, st-dwn, 0.85V±2%, 600mA, 3MHz, Vin>1.8V, HSST, CL
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.
XC9237E0LDER-Gprinted 6ULUSP-6CDC-DC converter, 6 pins, TorexDC-DC converterUSP-6C6 pinsTorex
Printed 6UL on the part. Easy to misread as GUI. Check that character with a loupe before you order anything.
What it is
DC-DC converter
Maker
Torex
Package
USP-6C
Pins
6
Details
DC/DC voltage converter IC: PWM-PWM/PFM, st-dwn, 0.85V±2%, 600mA, 3MHz, Vin>1.8V, LSST, CL
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.
XC9237E0LDMR-Gprinted 6ULSOT-23-5DC-DC converter, 5 pins, TorexDC-DC converterSOT-23-55 pinsTorex
Printed 6UL on the part. Easy to misread as GUI. Check that character with a loupe before you order anything.
What it is
DC-DC converter
Maker
Torex
Package
SOT-23-5
Pins
5
Details
DC/DC voltage converter IC: PWM-PWM/PFM, st-dwn, 0.85V±2%, 600mA, 3MHz, Vin>1.8V, LSST, CL
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.
15 more parts have no package on record
- FP6805-22BS7printed GU1Voltage supervisor, 3 pins, FitipowerVoltage supervisorNot recorded3 pinsFitipower
  Printed GU1 on the part. Easy to misread as GUI. Check that character with a loupe before you order anything.
  What it is
  Voltage supervisor
  Maker
  Fitipower
  Package
  Not recorded
  Pins
  3
  Details
  Microprocessor Reset Circuits With Adjustable Delay Time
  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 FP6805-22BS7, opens in a new tab
- IXD3235G0LD0R-Gprinted CULDC-DC converter, IXYSDC-DC converterNot recordedNot recordedIXYS
  Printed CUL on the part. Easy to misread as GUI. Check that character with a loupe before you order anything.
  What it is
  DC-DC converter
  Maker
  IXYS
  Package
  Not recorded
  Pins
  Not recorded
  Details
  DC/DC voltage converter IC: PWM, st-dwn, 0.85V±2%, 600mA, 3MHz, Vin>1.8V, HSST, CL
  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.
- IXD3235G0LD4R-Gprinted CULDC-DC converter, IXYSDC-DC converterNot recordedNot recordedIXYS
  Printed CUL on the part. Easy to misread as GUI. Check that character with a loupe before you order anything.
  What it is
  DC-DC converter
  Maker
  IXYS
  Package
  Not recorded
  Pins
  Not recorded
  Details
  DC/DC voltage converter IC: PWM, st-dwn, 0.85V±2%, 600mA, 3MHz, Vin>1.8V, HSST, CL
  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.
- IXD3237E0LD0R-Gprinted 6ULDC-DC converter, IXYSDC-DC converterNot recordedNot recordedIXYS
  Printed 6UL on the part. Easy to misread as GUI. Check that character with a loupe before you order anything.
  What it is
  DC-DC converter
  Maker
  IXYS
  Package
  Not recorded
  Pins
  Not recorded
  Details
  DC/DC voltage converter IC: PWM-PWM/PFM, st-dwn, 0.85V±2%, 600mA, 3MHz, Vin>1.8V, LSST, CL
  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.
- IXD3237E0LD4R-Gprinted 6ULDC-DC converter, IXYSDC-DC converterNot recordedNot recordedIXYS
  Printed 6UL on the part. Easy to misread as GUI. Check that character with a loupe before you order anything.
  What it is
  DC-DC converter
  Maker
  IXYS
  Package
  Not recorded
  Pins
  Not recorded
  Details
  DC/DC voltage converter IC: PWM-PWM/PFM, st-dwn, 0.85V±2%, 600mA, 3MHz, Vin>1.8V, LSST, CL
  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.
- S-817A19APF-CUITFprinted CUI4 pins, ABLICNot recordedNot recorded4 pinsABLIC
  Printed CUI on the part. Easy to misread as GUI. Check that character with a loupe before you order anything.
  What it is
  Not recorded
  Maker
  ABLIC
  Package
  Not recorded
  Pins
  4
  Details
  equivalent [1.9V LDO]
  Source
  Published code list
  Is it dead?
  Voltage, board powered, black probe on ground. Then ohms with the power off.
  Working, it reads
  Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.
  Dead, it reads
  Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
  Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
  Power off, input to output near 0 Ω: shorted.
  On the board:
  An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
  Compare:
  The same regulator on another rail or another board shows the right voltages and the right resistances.
  Watch for:
  Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.
  A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
- S-817A19APF-CUITFGprinted CUISeiko InstrumentsNot recordedNot recordedNot recordedSeiko Instruments
  Printed CUI on the part. Easy to misread as GUI. Check that character with a loupe before you order anything.
  What it is
  Not recorded
  Maker
  Seiko Instruments
  Package
  Not recorded
  Pins
  Not recorded
  Details
  Linear voltage regulator IC: 1.9V±2%, 50mA
  Source
  Published code list
  Is it dead?
  Voltage, board powered, black probe on ground. Then ohms with the power off.
  Working, it reads
  Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.
  Dead, it reads
  Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
  Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
  Power off, input to output near 0 Ω: shorted.
  On the board:
  An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
  Compare:
  The same regulator on another rail or another board shows the right voltages and the right resistances.
  Watch for:
  Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.
  A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
- S-817A22APF-CULTFprinted CUL4 pins, ABLICNot recordedNot recorded4 pinsABLIC
  Printed CUL on the part. Easy to misread as GUI. Check that character with a loupe before you order anything.
  What it is
  Not recorded
  Maker
  ABLIC
  Package
  Not recorded
  Pins
  4
  Details
  equivalent [2.2V LDO]
  Source
  Published code list
  Is it dead?
  Voltage, board powered, black probe on ground. Then ohms with the power off.
  Working, it reads
  Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.
  Dead, it reads
  Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
  Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
  Power off, input to output near 0 Ω: shorted.
  On the board:
  An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
  Compare:
  The same regulator on another rail or another board shows the right voltages and the right resistances.
  Watch for:
  Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.
  A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
- S-817A22APF-CULTFGprinted CULSeiko InstrumentsNot recordedNot recordedNot recordedSeiko Instruments
  Printed CUL on the part. Easy to misread as GUI. Check that character with a loupe before you order anything.
  What it is
  Not recorded
  Maker
  Seiko Instruments
  Package
  Not recorded
  Pins
  Not recorded
  Details
  Linear voltage regulator IC: 2.2V±2%, 50mA
  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.
- SMCJ154A-TRprinted GUL2 pins, STMicroelectronicsNot recordedNot recorded2 pinsSTMicroelectronics
  Printed GUL on the part. Easy to misread as GUI. Check that character with a loupe before you order anything.
  What it is
  Not recorded
  Maker
  STMicroelectronics
  Package
  Not recorded
  Pins
  2
  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.
- XC9235G0LD0R-Gprinted CULDC-DC converter, TorexDC-DC converterNot recordedNot recordedTorex
  Printed CUL on the part. Easy to misread as GUI. Check that character with a loupe before you order anything.
  What it is
  DC-DC converter
  Maker
  Torex
  Package
  Not recorded
  Pins
  Not recorded
  Details
  DC/DC voltage converter IC: PWM, st-dwn, 0.85V±2%, 600mA, 3MHz, Vin>1.8V, HSST, CL
  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.
- XC9235G0LD4R-Gprinted CULDC-DC converter, TorexDC-DC converterNot recordedNot recordedTorex
  Printed CUL on the part. Easy to misread as GUI. Check that character with a loupe before you order anything.
  What it is
  DC-DC converter
  Maker
  Torex
  Package
  Not recorded
  Pins
  Not recorded
  Details
  DC/DC voltage converter IC: PWM, st-dwn, 0.85V±2%, 600mA, 3MHz, Vin>1.8V, HSST, CL
  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.
- XC9237E0LD0R-Gprinted 6ULDC-DC converter, TorexDC-DC converterNot recordedNot recordedTorex
  Printed 6UL on the part. Easy to misread as GUI. Check that character with a loupe before you order anything.
  What it is
  DC-DC converter
  Maker
  Torex
  Package
  Not recorded
  Pins
  Not recorded
  Details
  DC/DC voltage converter IC: PWM-PWM/PFM, st-dwn, 0.85V±2%, 600mA, 3MHz, Vin>1.8V, LSST, CL
  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.
- XC9237E0LD4R-Gprinted 6ULDC-DC converter, TorexDC-DC converterNot recordedNot recordedTorex
  Printed 6UL on the part. Easy to misread as GUI. Check that character with a loupe before you order anything.
  What it is
  DC-DC converter
  Maker
  Torex
  Package
  Not recorded
  Pins
  Not recorded
  Details
  DC/DC voltage converter IC: PWM-PWM/PFM, st-dwn, 0.85V±2%, 600mA, 3MHz, Vin>1.8V, LSST, CL
  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.
- XC9262A0LD1R-Gprinted CULDC-DC converter, TorexDC-DC converterNot recordedNot recordedTorex
  Printed CUL on the part. Easy to misread as GUI. Check that character with a loupe before you order anything.
  What it is
  DC-DC converter
  Maker
  Torex
  Package
  Not recorded
  Pins
  Not recorded
  Details
  DC/DC voltage converter IC: PWM HiSAT-COT, 3.0MHz, 0.85V±2%, 1.5A, +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.

76 more parts have codes that begin with GUI

Codes that begin with GUI

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

LDO regulator, all SOT-23-6, 6 pins, all Analog Integrations.

AIC1953-I3GG6Aprinted GUI3GSOT-23-6
Printed GUI3G. 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
Analog Integrations
Package
SOT-23-6
Pins
6
Details
Linear voltage regulator IC: LDO, Dual out, Vout1/Vout2=1.6V/2.85V±2%, 600mA, +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.
AIC1953-I4GG6Aprinted GUI4GSOT-23-6
Printed GUI4G. 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
Analog Integrations
Package
SOT-23-6
Pins
6
Details
Linear voltage regulator IC: LDO, Dual out, Vout1/Vout2=1.6V/3.4V±2%, 600mA, +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.
AIC1953-I5GG6Aprinted GUI5GSOT-23-6
Printed GUI5G. 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
Analog Integrations
Package
SOT-23-6
Pins
6
Details
Linear voltage regulator IC: LDO, Dual out, Vout1/Vout2=1.6V/3.5V±2%, 600mA, +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.
AIC1953-I6GG6Aprinted GUI6GSOT-23-6
Printed GUI6G. 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
Analog Integrations
Package
SOT-23-6
Pins
6
Details
Linear voltage regulator IC: LDO, Dual out, Vout1/Vout2=1.6V/3.6V±2%, 600mA, +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.
AIC1953-I7GG6Aprinted GUI7GSOT-23-6
Printed GUI7G. 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
Analog Integrations
Package
SOT-23-6
Pins
6
Details
Linear voltage regulator IC: LDO, Dual out, Vout1/Vout2=1.6V/3.7V±2%, 600mA, +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.
AIC1953-I8GG6Aprinted GUI8GSOT-23-6
Printed GUI8G. 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
Analog Integrations
Package
SOT-23-6
Pins
6
Details
Linear voltage regulator IC: LDO, Dual out, Vout1/Vout2=1.6V/3.8V±2%, 600mA, +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.
AIC1953-IAGG6Aprinted GUIAGSOT-23-6
Printed GUIAG. 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
Analog Integrations
Package
SOT-23-6
Pins
6
Details
Linear voltage regulator IC: LDO, Dual out, Vout1/Vout2=1.6V/0.8V±2%, 600mA, +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.
AIC1953-IBGG6Aprinted GUIBGSOT-23-6
Printed GUIBG. 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
Analog Integrations
Package
SOT-23-6
Pins
6
Details
Linear voltage regulator IC: LDO, Dual out, Vout1/Vout2=1.6V/0.9V±2%, 600mA, +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.

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

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One code, several parts

Marking codes are not unique. In the standard code book, 6H on a SOT-23 is an NPN transistor, a varicap, an N-channel JFET, two digital transistors, a 3.6 V voltage detector: six parts from five makers. So a search 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

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2 parts are printed GUI

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Printed with a code easy to misread

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Codes that begin with GUI

Is it dead?

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One code, several parts

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