SMD code 392
Marking codes are not standardised, and the same code is reused by unrelated makers for unrelated parts. Below is every part in our tables printed with it, and any printed with a code that is easy to misread as it, from the manufacturers' own marking tables and published code lists.
392 on a chip resistor
3.9 kΩ
3.9 kΩ resistor, 5%
39 followed by 2 zeros. Three digits is normally the 5% series. The same marking also reads as 3.9 nF on a capacitor or 3.9 mH on an inductor, and nothing in the code says which; the body of the part does.
Other readings of the same characters, most likely first
- 3.9 nF capacitor
- 3.9 mH inductor
Check it with a meter
Lift one end and measure across it. A good one reads 3.9 kΩ within 5%. Measuring it in circuit reads the parallel combination of everything around it, which is almost always lower, never higher: well above 3.9 kΩ on the board is a fault. Open, or well above 3.9 kΩ, means it has failed: burnt, cracked or corroded. That does not change what to fit: the marking still says 3.9 kΩ. A burnt resistor usually means the part it feeds drew too much, so find that before fitting a new one.
On a transistor or diode body (SOT-23, SOT-23-5, SOT-89), 392 is a part code instead. Those parts are listed below.
3 parts are printed 392
Not sure which one you have?
Answer up to 4 quick questions and these 3 parts are ranked, with a meter test that settles it. It works on a dead part too.
PZM3.9NB2SOT-233 pins, NXPNot recordedSOT-233 pinsNXP
- What it is
- Not recorded
- Maker
- NXP
- Package
- SOT-23
- Pins
- 3
- Details
- 3.9V 300mW Zener
- Source
- Published code list
Is it dead? The meter test is below: Zener diode.
XC6104B533MRSOT-23-5Voltage supervisor, 5 pins, TorexVoltage supervisorSOT-23-55 pinsTorex
- What it is
- Voltage supervisor
- Maker
- Torex
- Package
- SOT-23-5
- Pins
- 5
- Details
- CMOS-IC: VDet 3.3V, 5%, Hst, ±Reset PPO, Wt=400ms, Rt=25ms
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
1 more part has no package on record
HZM3.9NB2Zener diode, RenesasZener diodeNot recordedNot recordedRenesas
- What it is
- Zener diode
- Maker
- Renesas
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Z-diode: 3.87..4.1V, 200mW
- Source
- Published code list
Is it dead? The meter test is below: Zener diode.
Is it dead? One meter test per kind
Parts of the same kind are tested the same way, so each test is here once. Each part above points to its own.
Zener diode
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.
Integrated circuit
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.
Printed with a code easy to misread as 392
One character differs, and it is one that is easy to confuse under a lamp. Each code has a page of its own.
Codes that begin with 392
For a marking with its end worn or burnt off. Each code has a page of its own.
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