ty wrote in message
...
N Cook wrote:
History , there was a smell of burning followed by cutting out.
Next time powered up high pitched squeel.
Now on powering up very muted output like half-wave and sometimes a
burst of
high frequency squeel but all at low level.
Nothing obviously burnt or over-heated inside.
Stable HT voltage. 4x 6L6
Same distorted sound on the line out.
Before testing the valves etc, anyone have any pointers ?

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/



high pitch squeal usually indicates dying preamp tube, but should have
no odor...

ty

I've not seen the track side of the main board but i'd expect to see trace
of overheating of a copper track through the polyester/glass

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/