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Hi all,
Very new to this forum, couple of nights ago my sons AVT50 after 5 years use emitted a puff of smoke - it wasn't in use at the time although a guitar was connected and it was of course switched on. He shut it down immediately. The 10 ohm resistor R58 is burned although not damaged and the associated C92 appears OK.
Searching around the net this seems to be a common problem and is caused by HF feedback/oscillation - presumably due to deterioration of some components.
We will replace the R58 and C92 (R58 will go to 1 watt) but I suspect this may not be the whole answer. Any advice on which other components might be involved?
Also, its obvious that R58 and C92 are only going to do anything at very high frequencies (way higher than audio) so the design must be expecting this problem, seems odd to include this circuit but not to make the components meaty enough to handle the problem?
Or am I missing something? Don't know much about this specialized type of Amp...
Geoff
Very new to this forum, couple of nights ago my sons AVT50 after 5 years use emitted a puff of smoke - it wasn't in use at the time although a guitar was connected and it was of course switched on. He shut it down immediately. The 10 ohm resistor R58 is burned although not damaged and the associated C92 appears OK.
Searching around the net this seems to be a common problem and is caused by HF feedback/oscillation - presumably due to deterioration of some components.
We will replace the R58 and C92 (R58 will go to 1 watt) but I suspect this may not be the whole answer. Any advice on which other components might be involved?
Also, its obvious that R58 and C92 are only going to do anything at very high frequencies (way higher than audio) so the design must be expecting this problem, seems odd to include this circuit but not to make the components meaty enough to handle the problem?
Or am I missing something? Don't know much about this specialized type of Amp...
Geoff
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