SMD code search: identify a part by its marking
1 part is printed 1042. 4 printed with a similar-looking code.
Not sure which one you have?
Answer up to 4 quick questions and these 5 parts are ranked, with a meter test that settles it. It works on a dead part too.
The only part printed 1042 in our tables
WD1042E-5
- What it is
- DC-DC converter
- Maker
- Willsemi
- Package
- SOT-23-5
- Pins
- 5
- 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.
Was it this one?
Printed with a code easy to misread
These parts are printed with a character that is easy to misread as what you typed. The odd one out is marked on each.
BL8534CC3TR42printed LD42SOT-89DC-DC converter, 3 pins, Shanghai BellingDC-DC converterSOT-893 pinsShanghai Belling
Printed LD42 on the part. Easy to misread as 1042. Check that character with a loupe before you order anything.
- What it is
- DC-DC converter
- Maker
- Shanghai Belling
- Package
- SOT-89
- Pins
- 3
- Details
- DC/DC voltage converter IC: PFM st-up, 4.2V±2%, 200mA
- 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.
R3134Q23EA2printed L042SOT-23-5Voltage supervisor, 5 pins, RicohVoltage supervisorSOT-23-55 pinsRicoh
Printed L042 on the part. Easy to misread as 1042. 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: 2.32V±1.8%, -Reset ODO, -MR
- 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.
XC6219D422DRprinted L D42USP-6BLDO regulator, 6 pins, TorexLDO regulatorUSP-6B6 pinsTorex
Printed L D42 on the part. Easy to misread as 1042. Check that character with a loupe before you order anything.
- What it is
- LDO regulator
- Maker
- Torex
- Package
- USP-6B
- Pins
- 6
- Details
- VR-IC: LDO, -CE, 4.2V±2%, 240mA
- Source
- Published code list
Is it dead?
Voltage, board powered, black probe on ground. Then ohms with the power off.
Working, it reads
Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.
Dead, it reads
- Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
- Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
- Power off, input to output near 0 Ω: shorted.
- On the board:
- An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
- Compare:
- The same regulator on another rail or another board shows the right voltages and the right resistances.
- Watch for:
- Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.
A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
1 more part has no package on record
R1190S042Bprinted L042RicohNot recordedNot recordedNot recordedRicoh
Printed L042 on the part. Easy to misread as 1042. Check that character with a loupe before you order anything.
- What it is
- Not recorded
- Maker
- Ricoh
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Linear voltage regulator IC: 4.3V±1.5%, 1A, +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.
3 more parts have codes that begin with 1042
Codes that begin with 1042
For a marking with its end worn or burnt off. Each one shows its full printed code.
TPT1042Q-DF6R-Sprinted 1042QDFN8 pins, 3PEAKNot recordedDFN8 pins3PEAK
Printed 1042Q. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.
- What it is
- Not recorded
- Maker
- 3PEAK
- Package
- DFN
- Pins
- 8
- Details
- Automotive Fault Protected High-Speed CAN FD Transceiver with
- Source
- Manufacturer datasheet
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.
TPT1042V-DF6R-Sprinted 1042VDFN8 pins, 3PEAKNot recordedDFN8 pins3PEAK
Printed 1042V. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.
- What it is
- Not recorded
- Maker
- 3PEAK
- Package
- DFN
- Pins
- 8
- Details
- Fault Protected High-Speed CAN FD Transceiver with Standby
- Source
- Manufacturer datasheet
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.
FMLD-4206Sprinted LD4206STO-3PFRectifier, 3 pins, SankenRectifierTO-3PF3 pinsSanken
Printed LD4206S. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.
- What it is
- Rectifier
- Maker
- Sanken
- Package
- TO-3PF
- Pins
- 3
- Details
- Fast Recovery Diode (VRM = 600 V, IF(AV) = 20 A, trr = 50 ns)
- 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.
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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.
- 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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