FIRST: DON'T WORK ON THIS AMP WHEN IT'S PLUGGED IN! THERE'S NO INTERLOCK.
DON'T STICK YOUR HANDS IN THE AMP WHEN IT'S ON!
Pull all three tubes and test them one at a time, in one of the sockets
other than the one in which the bad tube was previously inserted. If the
"bad" tube's filament doesn't light, it's truly bad and should be replaced.
If it does light, you probably have a bad socket, which should be replaced.
To test each tube, bring the drive up slowly and tune for max power, which
should be 400W-500W or so. Don't overdrive. Plate current should be about
300-350ma and grid current should be about 100-125ma.
What's the plate voltage meter reading?
73, Dick WC1M
--
FAQ on WWW: http://www.contesting.com/ampsfaq.html
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|