In article <op.tp77d0xemg0lsf@tu-x2pj5qeyp2u4>,
Stefan Trethan <
stefan_trethan@...> wrote:
> If stuff gets that hot in electronics there's a problem somewhere anyway.
Fact of life - valves get hot.
I have several times had to make PCBs to replace burnt out ones in old
commercial valve equipment. Admittedly the originals were Paxolin rather
than fibreglass but...
Usual scenario is the solder joints between the PCB and the valve-holder,
because of the heat and the cycling, start to go crystaline. They become
high resistance and "dry" which causes the generation of more heat which
passes back along the track softening the adhesive and causing the track
to lift off the board charring it at the the same time.