OR120 Schematics etc

[CrustyCakes]

I've got an Orange Overdrive OR120 (ser # 854) sitting on my bench. It came in not sounding nearly as loud as it should. It also blows the B+ fuse after about 30 minutes of rocking. The bias is turned all the way down, and if it is increased to 50% the amp get's noisy. At 75% the B+ fuse blows. I am replacing the power supply capacitors, since one of them reeds 300VDC to the shell. I discovered that the hard way.

At any rate.... the schematic at http://tdsl.duncanamps.com/schematics2.php?make=Orange is for a Graphic MK II, and it appears to be pretty much the same schematic as the OR120. Yes/No?

Anybody have an actual schematic for the OR120?

Is there any such thang as replacement transformers available in the event something worse has happened?

What about actual service manuals?

Thanks!

[CrustyCakes]

Closer inspection say close but no cigar on the match up. I really need to find a schematic for the OR120.

[fiveightandten]

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I've got an Orange Overdrive OR120 (ser # 854) sitting on my bench. It came in not sounding nearly as loud as it should. It also blows the B+ fuse after about 30 minutes of rocking. The bias is turned all the way down, and if it is increased to 50% the amp get's noisy. At 75% the B+ fuse blows. I am replacing the power supply capacitors, since one of them reeds 300VDC to the shell. I discovered that the hard way.

At any rate.... the schematic at http://tdsl.duncanamps.com/schematics2.php?make=Orange is for a Graphic MK II, and it appears to be pretty much the same schematic as the OR120. Yes/No?

Anybody have an actual schematic for the OR120?

Is there any such thang as replacement transformers available in the event something worse has happened?

What about actual service manuals?

Thanks!


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The Orange amp field guide should have all the schematics you need...

http://users.pandora.be/geertjacobs/orange_page.htm

Mercury Magnetics sells replacement trannys...but they're not cheap. www.mercurymagnetics.com

Do you have a decent steady neg voltage from the bais supply and a decent steady voltage coming into the plates and the screens? Have you tried it with different tubes?

-Nick