t-amp modding trouble

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Hi all,


OK, I think I've done some damage to my t-amp. The plane here was to use 2 t-amps to bi-amp. First t-amp is lightly modded, reboxed and replaced the input capacitors (C3,C4) with 2.2uF audio grade ones.

I received the second t-amp today, set to work reboxing it. Eventually I got the new input capacitors on and connected (not an easy job for someone with my skills) the amp ran AOK for about 2 mins and then cut out. Opened up the box, found that the chip is getting hot if the power is turned on. If you let it cool, still no sound. No signs of burning on the board, scorch marks etc etc etc.

Have I irreparably damaged the board? Anything I should try to salvage it?

Many thanks in advance,
Fran
 
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If the chip is getting hot you may have the outputs shorted to ground somehow. None of the speaker terminals can be connected to ground. Check that.

Also, it is possible that you have caused a DC offset with your inputs mods, happens all the time. There are plenty of discussions of this on the forum. Check the outputs with a volt meter. If you find more than 0.2 volts DC between + and -, then you have a problem.
 
OK, checked outputs every way I could for continuity and all checked out OK.


Then I tried what you said about the DC offset. I get about 3V on one channel and 5 on the other. The chip heats up over maybe 2 mins. Also, I only get sound on one channel, the other channel is ver faint.

Any suggestions welcome and I'll go and search the forum for this topic too.


thanks for the help,

Fran
 
OK,

I think I may have found the trouble. I reckon I've damaged the pad around C4 - right above where C4 is written. If I leave this disconnected I get a DC reading of <10mV. So obviously my desoldering of C4 has led me to this trouble, and now after all the poking, the pad beside the C4 label is gone too.

Would anyone know where else on the board I could solder the jumper to my replacement C4 cap? The trace just seems to disappear - perhaps to the other side of the board?

Thanks (again) in advance
Fran
 
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