1976 Peavey Classic 100 -Original Tubes

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1976 Peavey Classic 100 -Original Tubes

Postby WickedTuneDude on Mon Dec 29, 2014 11:38 pm

Trying to save some RockNRoll Junk. Just bought this Amp Because it was short $. I plugged it in and it powered on, then it started Smoking. It possibly had no output at the time. I think I was checking when I noticed the Smoke.

Significant amounts of smoke. The Tubes look older then the amp. So I want to replace them because I see no damage on the board at all and figure its what would go first.

The other thought I had is that for some reason the Main Power Transformer could be shorted? the wires seems to be a little discolored, possibly from the smoke.

I put a new fuse in it now it lights on briefly and blows the fuse.

What I'm wondering is?

1) Whats a good set of throwaway Replacement CRC-6L6 / 6L6GC Tubes to buy to see if it was just the Tubes?
2) Would it make sense to look into the Power Transfomer before I buy Tubes?

I don't own a Tube Tester. Bought have and can use a Multimeter.

Thanks for your time!
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Re: 1976 Peavey Classic 100 -Original Tubes

Postby WickedTuneDude on Tue Dec 30, 2014 5:19 pm

Also blows fuses without either Power Tube connected.
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Re: 1976 Peavey Classic 100 -Original Tubes

Postby PeterS on Wed Dec 31, 2014 4:44 pm

Could be the transformer but the most likely problem is bad power supply filter caps. Fairly cheap fix...
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Re: 1976 Peavey Classic 100 -Original Tubes

Postby WickedTuneDude on Wed Dec 31, 2014 10:23 pm

Those would be the Fairly Large Capacitors in Line with the Switch and Tied To Ground? There is No Discoloration to them.

(Paktron .22 +/- 20% 125VAC) .22 is Microfarads uF?
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Re: 1976 Peavey Classic 100 -Original Tubes

Postby PeterS on Thu Jan 01, 2015 6:38 pm

No, look for the largest cylindrical objects in the amp. Might be hanging under the chassis like the tubes do.
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Re: 1976 Peavey Classic 100 -Original Tubes

Postby Papa Dog on Fri Jan 02, 2015 3:15 pm

pics would help.
smoke is seldom a good thing.
when the amp smoked something was burning up. Whatever it is/was is now burned and I would not expect that amp to work unless/until whatever is burned has been replaced.
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Re: 1976 Peavey Classic 100 -Original Tubes

Postby WickedTuneDude on Fri Jan 23, 2015 6:14 am

So it was the Input Transformer that Smoked. (Hopefully it's not too Fried, Peavey and TMI have no knowledge of my EIA# or P/N, so a Replacement is probably going to be interesting to find)

And Fuses will blow without the 6L6GCs In Place. So my Filter Cap which is a (MDF 40 VDC 500 / MDF 20 VDC 500) could still be the culprit... I think.

Could I pull Leads off the CAP and/or Output Transformer with the Tubes removed and see if it still blows fuses?
Or should I just replace this Filter Cap? ::Probably the Input XMFR after I smoked it too::

Any Recommended Sites to Buy the Cap?
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Re: 1976 Peavey Classic 100 -Original Tubes

Postby PeterS on Fri Jan 23, 2015 4:50 pm

If it was my amp i would disconnect the filter caps and so (i.e. everything on the secondary side of the power transformer) and see if the fuse
blows, and measure some voltages. The goal is to assess whether the transformer is still working or damaged. I would not buy caps until I assessed
the PT and also sourced a replacement if needed, since that might be difficult/expensive.
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Re: 1976 Peavey Classic 100 -Original Tubes

Postby WickedTuneDude on Tue Feb 03, 2015 3:22 am

So its 100% the Input Transformer. Thing was practically Melted.

And I've bugged everyone I could about finding a replacement Transformer, Which most resembles a EH449 on the Classic B Schematic ( Same outputs as far as wire color and point to point) . But this Multitap Single Phase Transformer is hard to come by.

So this guy is headed to the Garbage-io. One last breathe on the forum! Thanks for all your help.
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