"N_Cook" wrote in message
...
Amp used for the first time, in 2 years of regular mains use, with a
generator. Works fine with no problems. Coincidence ?, next gig back to
usual mains supply, at power up, blows the mains fuse. The GZ34 is failed
both sides, 0 percent output . Inspecting the fuse it has failed at an end
,
not the central (T) section and otherwise complete wire shows no sag or
discolouration. So possibly mechanical failure of fuse. If fast make/break
intermittant action of the fuse wire at an end , would that knock out an
RR
valve? What in general happens in the failure of RRs ? I've only ever seen
75 percent , same as new, or 0 percent "goodness" at prescribed current
settings of the Avo valve tester.



I've had a number of GZ34s fail short circuit, or suffer from serious
flashover, and knock out fuses over the years, but I've always put this down
to saggy filaments or whatever, where the valves are mounted horizontally,
or upside down.

Arfa