SMD code 59S
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.
59S on a chip resistor
40.2 Ω
40.2 Ω resistor, 1%
EIA-96 precision code: 59 selects 4.02 from the E96 series and S multiplies by 10. These are 1% parts. The trailing S is also used as a decimal point, so this could instead be 59 Ω. Measure it before fitting a replacement. If it has failed and reads open or high, that settles nothing: measure the same position on a working board.
Check it with a meter
Lift one end and measure across it. A good one reads 40.2 Ω within 1%. Measuring it in circuit reads the parallel combination of everything around it, which is almost always lower, never higher: well above 40.2 Ω on the board is a fault. Open, or well above 40.2 Ω, means it has failed: burnt, cracked or corroded. That does not change what to fit: the marking still says 40.2 Ω. 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 (SMA, SOD-123F, SMAF), 59S is a part code instead. Those parts are listed below.
3 parts are printed 59S
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.
Zener diode, all Chenmko Enterprise. What differs:
MMBZ5259SPTSOT-233 pinsSOT-233 pins
- What it is
- Zener diode
- Maker
- Chenmko Enterprise
- Package
- SOT-23
- Pins
- 3
- Details
- Zener diode: 38.22..39.78V, Izt=5mA, Zzt=130, 225mW
- Source
- Published code list
Is it dead? The meter test is below: Zener diode.
MMCZ5259SPTSOT-233 pinsSOT-233 pins
- What it is
- Zener diode
- Maker
- Chenmko Enterprise
- Package
- SOT-23
- Pins
- 3
- Details
- Zener diode: 38.22..39.78V, Izt=5mA, Zzt=130, 225mW
- Source
- Published code list
Is it dead? The meter test is below: Zener diode.
MMHZ5259SPTSOD-1232 pinsSOD-1232 pins
- What it is
- Zener diode
- Maker
- Chenmko Enterprise
- Package
- SOD-123
- Pins
- 2
- Details
- Zener diode: 38.22..39.78V, Izt=5mA, Zzt=130, 225mW
- 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.
Printed with a code easy to misread as 59S
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 59S
For a marking with its end worn or burnt off. Each code has a page of its own.
Codes not listed here are printed on 11 more parts.
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