"N_Cook" wrote in message
...
A friend of a friend asked me about some mixer-amp, make unknown.
It works fine but every now and they see a blue flash through vent holes.
Presumably before the reservoir caps and a break at mains volts, but what?
A green flash from a seriously overloaded fuse rupturing, but that would
be
one-off, but what could give a blue flash ?

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



At this point, that's a bit like saying "I have a friend that has some kind
of vehicle with some wheels on, and sometimes it rattles. Anyone got any
thoughts on what it might be ?"

Do we even know if it is valve or semiconductor ? Valve flashovers can give
a pretty good blue flash without too much interuption to operation. I would
have thought that any flashover big enough to be seen on a semiconductor
amp, even at the mains end of things, would be associated with other
(audible) problems ...

Arfa