Hi Zolton,

If it is a zener diode then replacing with 1N4148 will not cause the power supply to work. Zener diode color codes not like resistors where there is a standard resistor color codes. For zener diode they are manufacturer's specific. A green stripe may represent 5 volt or could be other voltage. If the zener diode in the power supply acts as a protection diode, you can actually don't need to put in the zener diode and test the power supply first. If it works then you need to measure the line to check what is the DC volt. Once you know the Dc voltage then you can place a slightly higher voltage of zener diode. But you also need to know that not all zener diode in the power supply act as a protection diode.

Jestine

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I ran into a power supply having a broken diode. It's a little glass diode - like 1N4148 - with a green stripe and the anode terminal is painted white. Since it's bad, torn, no connection into either direction, so I cannot figure it out what was it originally. I have replaced it with an 1N4148 diode, but the power supply it's not working.

Thank You for Your help in advance!
Zoltan

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Hi Lee,

I suggest that you read through the comments as there are some info about the zener color codes. You can also visit this link http://pdf.datasheetcatalog.com/datasheet/rohm/rlz_series.pdf. There is no info on red color zener diode...sorry

Jestine

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I have one power supply is circuit board. How I need understand the zener diode color coding is red blue brown and zener diode color coding is red.Can you help me

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I have the same problem,l don't know what can l identify the exactly value of zener voltage on the one having blue band?

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17.6v

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Hi Tanja,

Ignore the black you will get either 5.4v (54 v) or 4.5 v (45 volt) and since there is no standard zener diode code it would be hard to tell the exact voltage. The best is you need to understand how the circuit work and find out roughly what voltage is running in that circuit.

Jestine

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Hi Aref,

What is the board marking? Is it ZD?

Jestine

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