6505 +112 COMBO

[Nashville 112]

I'm working on a 6505 + 112 COMBO and see some copper PC tracks that have obviously been cut by some type of abrasive "wheel". C43 has been cut loose from the cathode of V3. The ground has been cut loose from between R64 and R36. There is a "flying" lead between C11 and R101.

Is there a list of these mods and are they authorized by Peavey?

I have changed all the big electrolytic capacitors (13 of them) and replaced all 1N4003 diodes (11 of them) with 1N5402G diodes per instructions from John Fields.

The amp seems to be working so far based on signal tracing via a Tektronix oscilloscope and HP audio generator.

I'm curious as to what soldering equipment do you use in factory repair

Ron Wood
Waseca, MN

[j0nsnell]

Why change those diodes?
CR200 & 201 are high voltage suppressor diodes and your choice of diode will fail very quickly with a 1N5402G rated at 200v PIV!
3Amp diodes are not required anywhere! The issue is heat as the diodes are mounted incorrectly on the PCB. They should be mounted with 1/2" of free air between the diode and the PCB for ventilation and cooling.

[Nashville 112]

Why change those diodes?
CR200 & 201 are high voltage suppressor diodes and your choice of diode will fail very quickly with a 1N5402G rated at 200v PIV!
3Amp diodes are not required anywhere! The issue is heat as the diodes are mounted incorrectly on the PCB. They should be mounted with 1/2" of free air between the diode and the PCB for ventilation and cooling.

I believe you are not referring to the same amp. You mention CR200 & 201. They don't exist on the unit I'm working on. The changes I made (capacitors and diodes) were based on instructions from John C. Fields, an engineering manager at Peavey. All diodes I changed are in low voltage areas for the filaments, + and - 15 volt regulators and the bias for the 6L6 tubes. The schematic I'm working from was "signed off" (Released) by J. C. Fields. Maybe he will see these posts and respond. Thanks.