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Vintage threads from the first ten years

Classic 20 Power Transformer Dies

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1/19/2006 3:29 PM
William	Classic 20 Power Transformer Dies Hi My Peavey Classic 20 amp has killed two power transformers in a very short space of time. The fuses in the power transformer are not being affected at all. What do I do please?

1/19/2006 5:25 PM
Enzo	Hi William, glad to see you made it over here. You already have my thoughts on it, but hopefully some other insights will help here. For the benefit of others, you might list all that you have done so far in trying to solve the problem.

1/20/2006 12:21 AM

Hi Enzo

I will provide a list once I hear back from the repairer.

He reckons that all is well with the amp and can not see why the second power transformer would die except being a faulty power transformer from Peavey.

The Peavey distributor here in NZ has the transformer now so I am waiting with baited breath to see what happens.

If I get a new one and that blows then the list of fixes and changes from the peavey site from you guys will go to my repairer.

I would have thought that the repairer is up to scratch and on his game but we will wait and see.

My repairer was of the view that the amp is poorly designed and that the power transformer is unsuited for the application.

I trust Peavey gear and am loathe to get this guy too upset.

William

1/20/2006 7:14 AM
KB	Hey William, Dang now you know where tmenzo and I hide out at . Hopefully all will work out this time. I personally don't think the C-20 is underated more than I think either the tech made a mistake or just bad luck. You don't think it's possible that they may have sent you a 120vac the first time do you, KB/Cajun

1/21/2006 11:59 PM
William	I don't think so. I eyeballed both transformers and they have the same part number on them. I think it's a great amp and hopefully it will be up and running soon.

3/19/2006 7:56 AM

Dead power transformer without blown primary fuses is very often a short on the filament winding.

With the huge step down from 120 or 240 to 6.3V, the filament winding does not pull much primary current even if the secondary is shorted, because the leakage inductance and primary resistance keep things in bounds. However, the 6.3V secondary sits there and cooks until the heat melts insulation, and then you have a dead PT.

Check for a heater short, and put a fuse in the heater winding before you put the next PT in.

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