Peavey Windsor Studio No power issue

[anderson89]

Greetings everyone, new guy here.

Ive got a peavey Windsor on my bench. trying to resolve a no power issue. has continuity through the board. fuses on the board are good.
Im about to pull the transformer apart to check the fuse inside it.  there should be continuity through the primary to the other wires correct?
im learning how to to work on tube amps and am needing some assistance.
what do you guys think?


so, update. I checked for continuity after the thermal fuse and wham-o that's what it was.

[anderson89]

So, put a new fuse in the transformer. that fixed that issue. got everything plugged back in per the schematic.
powered into standby. tubes heated. turned power on and the power tube lit momentarily. got a little sound and then the capacitor on c7 blew again (already replaced at start of repair) any ideas?

[Williamblake]

What else have you replaced so far? And there should be no continuity from the primary to anything but the primary. 

[anderson89]

all I have replaced was a 100 microfarad cap on c7 and the fuse in the transformer. that's what I meant about the continuity across the primary windings. sorry about that. like I said after I powered the amp back on it powered up fine until I took it off standby. im still learning about working on tube amps. ive got a long way to go. I included the schematic if youre interested in taking a gander

[Williamblake]

C7 is the powertube cathode bypass capacitor in this single ended amp. Did you have a unusually high voltage at the power tube cathode? But i would pull the tubes, drain the caps and check the transformer, powersupply rail and tube pins for correct resistances to ground and B+ before plugging it in. Hopefully you will step on something odd but your powertube seems to be shorting so maybe you will not use it anymore / test it in your singers amp first?

Only joking, of course i wouldnt drain the caps. What could go wrong?

[anderson89]

Im going to go back and check all my voltages. ive got multiple tubes so I can test that too. don't drain the caps and get a jolt better than coffee.
10-4 good buddy.
Im very green when it comes to amp repair. I understand what the components do individually but still learning on how it all works together.

[PRR]

> there should be continuity through the primary to the other wires correct?

No.

[anderson89]

I appreciate the help guys. the continuity between the hot and neutral was what I meant. not to the other side of the wires, to the heaters,hi and low voltage. any good resources on learning how to diagnose the issue im having (read up) I really appreciate it. im new to tube amp repair and want to do this right.

[PRR]

Primary should be a few Ohms (2 to 20).

High volt secondary, hundreds of ohms. 6V secondary often under 1 Ohm (many meters will not read less than 1 Ohm).

Other than this: any winding to any other winding or to core must be "infinity", over 10 Megs, like probes not touching.