zaphod wrote:
Fuse popping is usually a sign of a short in the amp, or sometimes the fuse itself was weak. I don't see how that zener would be the cause. Even if it blew you would just get around 15V higher B+, like you would when the amp's set for KT66s.
To troubleshoot, is there a means to bypass the switch completely to verify if the short is past that? That's the only area of the amp that I'm not confident in my wiring of.
zaphod wrote:
On the nuts??? I hope you meant turrets...
Actually, this was with the secondaries disconnected from the turret board - I just meant that they were measuring right at 350v. "On the nuts" meaning right on.
zaphod wrote:
So you want to disconnect the CT to ground connection? I don't see much point in doing that if you've still got the secondaries connected to the rectifiers. If you want to disconnect the CT, then also disconnect the PT connection to the rectifiers. Check the OT primary connections and power tube connections very carefully for shorts. That's where most of the current goes when you take the amp out of standby, and anything wrong around there could blow a fuse.
It's blowing before I take it out of standby - the pilot light comes on for 1-2 seconds, then the fuse pops.
The spot that I wanted to pull was the B+ line past the rectifier diodes that runs to the power tube switch - that would show me if the short is in the rectifier or past that. Is that a safe spot to pull to measure the initial B+ and test for shorts, or would that cause trouble?