On Mon, 14 Jun 2010 14:19:32 +0100, tony sayer
wibbled:

Yes that sure sez that they can fail, but that old Grundig portable
we've got built sometime on 1958 is still going .. nice tone too, 'tho
thats prolly Germanium trannies in that!..

The old QUAD 33/303 my missus uses for her audio is 1967 vintage
original semis, caps changed and still to spec)..

And germanium wasn't immune either. My old dad had a germanium
"receiver" (tuner + amp) and it was forever, after about 10 years of
service) frying the power output bipolars (I guess heat related doping
migration - failure was usually gradual). They were a bugger to get too -
but just about possible. The circuit diagram did have DC test voltages at
various points which made fault finding fairly simple with nothing more
than a multimeter. It got serviced 2 or 3 times by us and was still
working (sort of) when about 35 years old. Only a 25W stereo amp too -
into 15W speakers and turning it up to half max would blow your eardrums
off. The 1/10 button remained depressed for most of the time.



--
Tim Watts

Managers, politicians and environmentalists: Nature's carbon buffer.