Iain Churches wrote:
"Keith G" wrote in message
...


OK, don't know about you lot but I'm just about done with checking here to
find nothing doing, ..........



We're all too busy fixing the miriads of Chinese valve amps
that seem to have been dumped on Europe and Scandinavia:-)

I have a fixed bias PP amp on my bench that has 10mm
skeleton pots for bias adjustment.

The owner who imported it directly, told me that it
worked only at very low power when it arrived, so
thinking it had been damaged in transit, he took it
to a local TV repair chap. He soon found the problem,
there was, and never had been, no connection between
the bottom end of the OPT secondary and the ground
terminal:-(

?

Do you mean the secondary wasn't connected to the LS terminal, or it
just wasn't grounded? the former should result in no output at all, and
the latter should make no difference to the output.


It looks like there might be an opportunity for someone
repairing these amps on a regular basis, to make
good money. At least there is an assured constant supply
of work. The trouble is, you can't spend much more
than an hour max, or the repair has cost half of the price
of the amp:-)

I have seen several of these now. They all bear a remarkable
similarity and have a generic PCB which can be used for
any number of different versions. Fiendishly cunning these
Chinese:-)


Hmm, I just fixed one that had a valve rectifier that was designed to
drive into a max of 4uf, and it was using 100uf. Oddly, the rectifier
had failed. The amp was only earthed via its phono sockets (the IEC
earth was unconnected) and it oscillated at 60Khz when running.

Apart from that, it was a cracker :-) (other than it didn't sound very
nice).

--
Nick