Peavy Backstage 30 Schematic Help

Pooh BearMarch 20, 2012

I'm trying to find a spec for a diode on the circuit board.

The diode is different than the others. And is zapped.

I can't read a part number on or near it.

Here is a part of the schematic:

I need the specs on those diodes. Hope someone can help.

The entire schematic is linked below.


Pooh Bear

Here is a link that might be useful: Peavy Backstage 30 Schematic

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All 4 diodes are all 1N4003.
It is written right on the schematic.
Google that part number and
you will find a 'spec sheet'
Also, you will find where
you can order them from.
I don't understand why one
would be different from the others
unless someone replaced it before.

    Bookmark   March 21, 2012 at 9:27AM
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Pooh Bear

That's all I could think of: Somebody replaced it before.

I finally figured it out after I posted this. 1N4003.
I didn't see it until I was looking at the blown up picture above.
The new Peavy part number is 70464003.
Silicon rectifier 5 amp 200 PRV DO-41 package.


Pooh Bear

    Bookmark   March 21, 2012 at 12:44PM
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A 1N4003 has a 1 amp rating not 5 amp. It is one of the most common diodes around and you can easily find them at Radio Shack.

I would just replace all four since they may be breaking down due to age anyway.

I do highly recommend replacing the filter capacitor as well since the amp could be from as early as 1977 (according to the schematic). Electrolytic capacitors dry up and can cause hum in the audio, component failure, and are the most common cause of the diode failure in the power supply like you experienced.

Your link is gone but I think it was a 2200 ufd @ 50 volt electrolytic - should be easy to find as well.

    Bookmark   March 21, 2012 at 3:41PM
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Pooh Bear

I went back and checked, it was 1 amp.
And the cap is 2200 ufd.
After I knew what I was looking for they were easy to find.

Thanks for the help.

Pooh Bear

    Bookmark   March 21, 2012 at 7:23PM
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