Custom Vibrolux Reverb volume issue

[harleyboy2112]

I have an amp on the bench that's testing my troubleshooting skills real good.
It's a Fender Custom Vibrolux Reverb. It's a PC board amp with the tube sockets mounted to the chassis and leads from the board to the sockets.
The issue is the volume controls on the amp. All the way down there is still signal coming through the amp, as the volume gets to about 3 the signal drops. After 3 the signal starts coming back again. It's this way for both the normal and bright inputs & volume controls.
I'm having a tough time pinning this one down. I've tried swapping tubes along the signal path & nothing changed. Voltages seem good.
I should note also that as I was testing it on my bench I noticed a little arcing around the speaker out jack. The jack was loose and not getting a good ground. I tightened the jack, no more arcing.
Any help would be appreciated.
Thanks!

[xtian]

Measure resistance from volume wiper to ground, make sure you can get down near 1 ohm.

[Stevem]

Do you have a O scope?

[harleyboy2112]

Yep I have a scope, I couldn't live without it
This ones a head scratcher for sure. I've been trying to pin down the problem & here's what I've found.
I pulled V3, V4, &V5 and it's still passing signal to the phase inverter. It's a weaker signal but still a clean signal and it's .7 volts.
The volume issue is still there, so I'm assuming however this signal is getting through is my issue.
Now to find out where in the heck it's picking up the signal. It acts like there is still a tube in V4.

[sluckey]

Temporarily clip another 22µF across C35. Node X feeds a lot of circuits and can provide a lot of sneak paths for signal if it starts drying out.

[TUBEDUDE]

Those newer schematics certainly have all the info you'd ever need, but damn, I find it impossible to flow through the layout quick and clean to get the overall topology first. The beauty of the "schematic" part is visually constipated with alphanumeric info. I'm just getting old I guess.

[harleyboy2112]

I owe Sluckey a beer
I replaced C35 which was mounted on the main PC board. I then thought I should check out the caps under the cap pan. I found 2 caps that were starting to leak so I ended up replacing all the power supply caps.
Problem gone! The amp sound great now.

Thanks for the help!

[Stevem]

Be sure to do the bias filter cap too !