Citation II help!

[James Cox]

Alright guys so I'm pretty bummed out here. I have a citation II that I picked up about 6 months ago that had been restored to stock values and worked perfectly aside from a little more background noise than I expected. I decided since I had pretty good luck restoring a few tube amps and receivers in the past I'd install Jim Mçshanes upgraded power supply level 1 and 2 kits. I knew when I started that my work was cut out for when I noticed how messing and tangled all the wiring on the power supply board was. The previous owner had removed all the cam and replaced them with individual electrolytic s and had so many random.jumpers it was hard to make sense of it. I pushed on anyway and just decided to work very slowly and meticulously 1 cap at a time. When I finished it looked good and matched up with the schematic the best I could tell so I fired it up. Powered on fine with no smoke so that's always a good sign but when I hooked up my source to test I noticed I only had sound coming from the left channel and the bias meter no longer responded to the bias pots in the back! I traced out all my wiring against the schematic for the boards and bias pots and everything seems to match up. I spoke to Jim and although he was very helpful he seemed like he didn't really have much time to help me figure it out so since you guys have been super helpful in the past I figured Id reach out and see if we could figure this out. I'm thinking maybe a wire has gotten lost in the shuffle somewhere because the guy who worked on it before me had such a Tangled mess of wires and ground jumpers on the board it's very possible one may have gotten lost or cut in the process. I took some voltage readings from V8, V10 and the c14 capacitor and they are definitely off by a bit.
On c14 I get 255v on the positive terminal and 500v on the negative.
V8:
1: 0
2: .2 VAC
3: 500 vdc
4: 490 vdc
5: -51 vdc
6: 411-490 vdc (jumpy reading, may want to try this one again)
7: .3 vac
8: 0

V10:
1: .1-.3 vac
2: 3.3 vac
3: 500vdc
4: 500 vdc
5: -60 vac
6: 500 vdc
7: 3.3 vac
8: .2 vdc

Hopefully those readings help point me in the right direction. I've not messed with either turret board aside from installing the film bypass caps from the kit.
I can post some pictures if necessary and if anyone has pictures of their power supply they want to post that would be super helpful.

 

[Selmerdave]

I would check that V8 pin 6 again, there's a 270-ohm resistor that goes from pin 4 to pin 6, just make sure it's properly soldered/attached. Pin 4 and 6 should be the same readings. We'll assume V10 pin 5 is a VDC reading.

I recall having a similar issue that had to do with T4 and T3, with some kind of ambiguity in the McShane instructions (which are otherwise outstanding). I'm not sure I'll recall at the moment but I'll look for evidence of what I did before. Your bias readings look pretty good so as long as the pots adjust the bias and you can get the correct current at each tube, you're basically in business but obviously you want the meter to work and I'll try to remember the issue there.

 

[James Cox]

Oh yeah that was my mistake. V10 pin 5 was definitely in vdc. I'll be back at the shop tomorrow and can mess with it more then and make sure the bias pots adjust the change the bias. I was so frustrated when the meter wouldn't work that I didn't even try haha. I did double check my readings though and V8 pin 6 is actually 490 I just had a bad connection with my probes when measuring. The 270 ohm resistors are fine. My main issue I'm trying to figure out now is why I no longer have a right channel. I can live with the meter not working but I think when I clear up the right channel problem the voltages will balance back and out the meter will work as well. Like I said everything worked before I decided to fiddle with it and upgrade the power supply board.

 

[Selmerdave]

Because the amp isn't in my possession it will take me a bit to go through past emails and photos to find if I had something similar, but I do recall some kind of issue that strangely began quite a while after doing the work (it was a 100% rebuild with full McShane mods). IIRC I found the issue by comparing left and right channels at T3 and T4, and something was different there. I have zero explanation for why it worked before but then required a change there, but after making the change the meter worked as usual again and I think there may have been a similar accompanying issue with a channel going out. Not 100% positive about all of that but I think most of it is right...

 

[James Cox]

Ok so I figured out the dead channel issue today. My speaker on my bench was unhooked haha. Both channels work now but the meter still doesnt. Id like to get the meter figured out before I finish these last few mods (triode switches, inrush limiters, bias resistors, and transformer ground mod. I've set aside some time to focus on troubleshooting tomorrow. In the meantime I'm going to message Jim and let him know what I've got going on now