Diagnosing bad 9-pin sockets

[ViperDoc]

OK, I have 6.5 VAC between pins 4 and 5 on the EL84 sockets, 6.4 VAC between pins 4:5 and 9 on V3, 6.3 VAC between pins 4:5 and 9 on V2 and...drum roll...
NO VOLTAGE BETWEEN PINS 4:5 AND 9 ON V1.

I took the tubes out and ran a continuity test. Diagnosis: BAD HEATER WIRE BETWEEN V2 AND V1 ON THE RED SIDE. When I soldered the coming and the going wires, I only got solder on the top wire; the bottom was dry. I clipped it, re-soldered it and VOILA! I have continuity down the entire chain now.

Which leads me to my next dumb f^ck move. When I pulled the preamp tubes to check the voltages, because I was in a hurry and being careless, I forgot to put a speaker cable in the speaker jack. What I actually should have done was pull all the tubes. Now I'm blowing MAINS fuses.

Maybe I just buried my tranny?

[xtian]

It takes a lot of effort to burn a transformer. More like you soldered the heater and shorted it to the chassis or something. Pull all tubes, use your bulb limiter (you have one, right?) and make sure you're not drawing too much current.

[Mac Dillard]

And, drum roll please, once again Mr Sluckey is dead on with what the problem was...I can giggle about it because I got caught with the same problem and Steve had to teach me the proper way to measure heater voltage....

[ViperDoc]

It takes a lot of effort to burn a transformer. More like you soldered the heater and shorted it to the chassis or something. Pull all tubes, use your bulb limiter (you have one, right?) and make sure you're not drawing too much current.

Thanks, xtian. I did some work on the heater wires, pulled every tube, put the amp on the bulb limiter and was able to power it up and have the amp power indicator lamp stay on, no fuses blown. The 40W incandescent bulb on my limiter, incidentally, didn't light up at all. I can place it directly into a socket and it lights up just fine. Not sure about that one--I thought it would at least be dimly lit. This is only the second time I've used it. I was able, however, to verify 6.5 VAC on V1 now across the heaters, so I'll take that as a win.

[ViperDoc]

YO!!!!

Thank you all as always for your kind help. Thanks to everyone here, I was able to power this up fully after a thorough differential and a few corrections. All tubes are lit, the amp is fully functional and, in all honesty, is ***DEAD SILENT***. And it sounds fantastic!

I tested it through my Scumback 212, but I'm going to put this baby into a 1210 combo cab with a Celestion G12M-65 Creamback and a 10-inch Celestion Gold. It should sound great with that.

A couple of observations:

1) Switching the amp from full power into standby has a nice switch pop. Do you simply solder a resistor across the standby switch to handle that? How do you select the value?
2) There's quite a bit of fizz at higher gain settings, and there appears to be no fizz cap on the board like I'm used to seeing. Any problem just adding one?
3) I have low wattage amps that are much louder than this amp. At the same wattage rating, what makes the most difference?

Thank you all again!

[pompeiisneaks]

I never use my standby switch and omit them from any of my builds. They're pointless. If you need a 'mute' get a volume pedal

~Phil

[ViperDoc]

I know there are haters, all good. But let’s say I had one...what would you solder across the switch? I see all kinds of recommendations.

[sluckey]

I know there are haters, all good. But let’s say I had one...what would you solder across the switch?

I'd put a short length of AWG 22 solid conductor wire across it. I do have amps with STBY switches and I have others without STBY switches. But I seldom use a STBY switch unless the amp is on the bench. I do find them useful when on the bench.

Here's a short read on Merlin's opinion...

http://www.valvewizard.co.uk/standby.html

[ViperDoc]

1) Mic drop noted.
2) Gut-laugh reported. OMG.