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F1 is the main fuse in the IEC connector. It is good or the filaments would not be lit. IMO, the next step would be to pull the output tubes, fire up the amp, and check the voltages on the output tube sockets. Let's see if B+ is getting there. Be careful of slipping probes and that you don't get jolted by the high voltage that should be there. Pick a socket, measure, and post voltages here.
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"I took a photo of my ohm meter... It didn't help." Enzo 8/20/22 -
Double checking for good measure:Originally posted by The Dude View Post
Yank all four 6L6s, power up the amp, clip the black lead to the chassis, set my multimeter to 200v DC, take it out of STANDBY, and (with my left hand firmly in my ass pocket and no jewlery on) probe pin 3 of each power tube socket to see if the problem is upstream or downstream?Comment
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Yes, but 200VDC range is not high enough. Highest range DC or if limit of meter is 200VDC you will need a better meter.
You are determining whether the power supply section is giving the tubes their operating voltage.Originally posted by Enzo
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Most cheap meters have a 500 to 750V rated DC range.
It is actually a 2000V DC one, next decade step abov 200VDC, *BUT* for safety reasons they do NOT want you to go that high, in any case it should be enough to measure most amps.
IMPORTANT: measure plate (pin 3) voltages with absolutely no signal in, and all controls set to 0.
Around 500VDC is the *idle* voltage but when driven it will definitely reach over 1000V peaks above ground
and if over driven into a speaker, up to 1500V peak.
And if you forget to plug the speaker, yet drive the amp fully , peaks can reach many KV ... thatīs why OT get punctured insulation and shorted.
I shudder thinking at your hands reaching those plates with a cheesy 300 to 600V rated test probe and wires.Juan Manuel FaheyComment
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