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SMD code 41

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.

3 parts are printed 41

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.

  • AO6401ASOT-23-6P-channel MOSFET, 6 pins, Alpha & Omega Semiconductor
    What it is
    P-channel MOSFET
    Maker
    Alpha & Omega Semiconductor
    Package
    SOT-23-6
    Pins
    6
    Details
    P-channel MOSFET (8-60 V)
    Source
    From the manufacturer's datasheet

    Is it dead? The meter test is below: P-channel MOSFET.

    Datasheetfor AO6401A, opens in a new tab
  • AO6401ALSOT-23-6P-channel MOSFET, 6 pins, Alpha & Omega Semiconductor
    What it is
    P-channel MOSFET
    Maker
    Alpha & Omega Semiconductor
    Package
    SOT-23-6
    Pins
    6
    Details
    P-channel MOSFET (8-60 V)
    Source
    From the manufacturer's datasheet

    Is it dead? The meter test is below: P-channel MOSFET.

    Datasheetfor AO6401AL, opens in a new tab
  • EIA-96:410603Precision resistor (EIA-96 code), 2 pins
    What it is
    Precision resistor (EIA-96 code)
    Maker
    Not recorded
    Package
    0603
    Pins
    2
    Details
    EIA-96 precision chip resistor, significand 26.1; the printed mark adds a multiplier letter (41A = 261 Ohm, 41B = 2.61 kOhm)
    Source
    Added by hand from a published table

    Is it dead? The meter test is below: Resistor.

    Datasheetfor EIA-96:41, opens in a new tab

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.

P-channel MOSFET

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

Working, it reads

Red probe on the drain, black on the source: 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. 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.

Resistor

Ohms range, across it, power off.

Working, it reads

Its marked value, within tolerance. On the board it reads the same or lower, because everything around it sits in parallel.

Dead, it reads

  • Open: burnt, cracked, or eaten through by sulphur. The commonest failure.
  • Well above its marked value: drifted high.
  • On the board, clearly higher than its marked value: it has failed, since the board can only pull a reading down.
On the board:
A reading lower than marked on the board proves nothing; lift one end. A reading higher than marked is a fault even on the board.
Compare:
The same position on another channel usually carries the same value, and so does the matching part on another board.
Watch for:
A burnt resistor usually means the part it feeds pulled too much. Find that before fitting a new one, or it burns too. The marking, not the reading, says what to fit.

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 41

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 41

For a marking with its end worn or burnt off. Each code has a page of its own.

Open this in the search to correct a character or try another package.