Soldano Astroverb 16 Reverb Hum

[g1]

Not 100% sure what you mean. If they are wires routed near traces, then your idea may work (changing lead dress).
Another approach would be powering the heaters with a 6VDC source.

[Helmholtz]

Any signs of a burnt/carbonized board?

[telecaster]

helmholtz - I see no evidence of burning or overheating anywhere on the circuit board.

Today's update - I went ahead and cut the trace between the 47K resistor and the parallel 220K/Reverb pot. I replaced it with a coaxial wire, grounded at just the Reverb pot. The hum is reduced, but is still unacceptably high. I measured 0.112VAC at the 22nF cap, compared to 0.6VAC prior to my modification.

[telecaster]

Latest update - I pulled the Reverb Pot (PC mounted) to isolate the wiper connection to V3.a pin 2. I measure 50mVAC on V3.a pin 2. Is this simply because that pin is floating now?

I started looking closer at V3 and noticed something strange (picture attached). It looks like a Dremel wheel cut between pins 5 and 6. Maybe it arc'ed between the 2 pins and someone cut the carbon bridge?

Any ideas for what to try next?

[telecaster]

I replaced the Reverb pot since I had the original out anyway, no change nor did I expect any. Summary so far: although replacing part of the land pattern with coax lowered the measured hum quite a bit, it is still way too loud and completely overpowers the dry signal.

I'm looking for any suggestions on what else to check or try, anyone?

[g1]

I'm looking for any suggestions on what else to check or try, anyone?

Try grounding the junction of the 22nF and 47K of V4b circuit. Hum all gone even with reverb pot up?

[telecaster]

Try grounding the junction of the 22nF and 47K of V4b circuit. Hum all gone even with reverb pot up?

I grounded the 22nF/47K junction and there is still hum, although reduced in volume.
With the junction grounded, and Reverb all the way up, V3 pin 2 measures 0.2VAC 60Hz peak-to-peak, vs 0.7VAC 60Hz peak-to-peak with the junction not grounded.

[g1]

I grounded the 22nF/47K junction and there is still hum, although reduced in volume.
With the junction grounded, and Reverb all the way up, V3 pin 2 measures 0.2VAC 60Hz peak-to-peak,

That still seems substantial. My guess would be there may be some board conductivity/defect. Which might also explain the dremel work at V3 if not due to arcing.