red hot transformer?

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marko said:
i'll have a poke around, could be this as some of the anodising on the transfomer wiring is slightly scorched....


try twisting with something while you play music and see if it comes and goes. look for a powdery substance between the shorted windings. they often short where the leads bend down to go into the board. if you can find the short you may be able to isolate it with kapton tape or new epoxy.
 
Might your amp be suffering from simultaneous conduction in the transistors (FETs on my amps) that drive the transformer's primary? If so, this could be caused by a damaged gate drive circuit or by the use of replacement FETs having larger gate to source capacitances than the drive circuit was designed for.
 
this is the amp, it's a bbg ryval by phoenix gold, it play fine for a few minutes then the transformer gets too hot to touch, i've ohmed all the devices out and they seam fine....

also the trasformer starts to very slightly smoke!!
 

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Pull the rectifiers out of the circuit. If the current draw remains high, you know the problem is in the supply. If the current draw goes down to ~1 amp, the problem is in the audio section.

After pulling the rectifiers, you need to put the board back in the sink and clamp the transistors down tightly. High current draw will destroy parts in seconds if they're not clamped to the sink.
 
hi all, i just got round to looking at this again as it's sunday and i'm board!

i pulled the rectifiers out and powered it up, within seconds the transformer was too hot to touch!! i didn't do a current draw check but i'm certain it would be high still...

do i have a shrorted transformer? i guess the only way to tell is to pull the transformer and do continuity tests..
 
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