Author Topic: Need help identifying a zener diode  (Read 769 times)

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Offline tobor

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Need help identifying a zener diode
« on: February 08, 2016, 03:41:26 am »
So, I'm refurbishing my AR X-06 receiver, and on the main power supply board, there is a broken zener diode.  The service manual references is as a UZ-20 (M, H) Zener Regulator.  That's not enough information for my limited experience to figure out what the appropriate specs for a replacement would be.

I'll attach the schematic for the board as well as a photo.  It is component D903.  D904 is an identical component, so, one solution that comes to mind, would be if I could determine through testing what the specs are on D904.  However, if I do so, I need to be careful not to destroy it as well.

Any help, on either a direct ID from the description, from it's use in the circuit, or on a method of determining the specs of the good component with little or no chance of damaging it, would be greatly appreciated!

Offline blueskull

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Re: Need help identifying a zener diode
« Reply #1 on: February 08, 2016, 03:47:07 am »
Since it says +-28.4V output, and allowing 0.7V drop on both transistors, I think both zener diodes are 27.7V ones. You have better luck finding 27V ones.

Replace BOTH of them to get symmetric voltage, so you do not have power on thump in your speaker.

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