Fender Silverface champ noise issue

[Helmholtz]

Measured DC voltage at the input jacks and there is nothing.

Did you have a plug in the input jack while measuring? Otherwise the jack will short any voltage.
Can your meter measure mV?

If your guitar pots are only scratchy with this amp, I'd expect some DCV.

[beedoola]

Did you have a plug in the input jack while measuring? Otherwise the jack will short any voltage.
Can your meter measure mV?

If your guitar pots are only scratchy with this amp, I'd expect some DCV.

yeah, had a patch cable plugged in.

I saw enzo’s post with turn schematic.

[vintagekiki]

I measured some of the voltages ...

Question
How much is the mains voltage?
For which primary voltage is provided PT, 100, 117 or 120VAC?

A higher AC voltage at the 5Y3 anodes will give a higher DC voltage at the first elco and at all other tubes.
The AC voltage at the 5Y3 anodes is 357VAC (365VAC at CBS Fender Champ) and it is within the predicted limits.
Voltages may vary in the tolerance relationship 10 - 20%.
After you did repair Champ as you described, what the sound is after the repair. Is it clean, or is it still have transient phenomena (noise or similar)
I guess all the tubes in Champ are new (not like new)

[Chuck H]

Did you have a plug in the input jack while measuring? Otherwise the jack will short any voltage.
Can your meter measure mV?

If your guitar pots are only scratchy with this amp, I'd expect some DCV.

This ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

[vintagekiki]

10 minutes of time, .022u capacitor and 1M resistor fixes all the described Champ problems if amp is properly repaired and brought into mint condition.

[Helmholtz]

10 minutes of time, .022u capacitor and 1M resistor fixes all the described Champ problems if amp is properly repaired and brought into mint condition.

What software do you use to edit original schematics?

[vintagekiki]

What software do you use to edit original schematics?

I don't understand the question, in relation to the title thread.
When you ask, any which online.

[Helmholtz]

I don't understand the question, in relation to the title thread.
When you ask, any which online.

Sorry, unrelated to thread topic.

I'd like to learn something.

I like how you modified the original schematic and am asking what software you used for this.

[vintagekiki]

I'd like to learn something.
I like how you modified the original schematic and am asking what software you used for this.

I'm an old-timer (y74) so such programs I use.
I use the good old Xp, and editors that Xp supports. These are PhotoEd 3.01 and Photoshop 5.0.
For the graphic symbol bank, I use symbols from factory schematics and then copy / paste. A text editor exists in Photoshop.
It's not very practical, but it's usable.
Tip
If you decide to do this kind of work, it is best to make your choice (bank) of symbols (resistor, capacitor, tube, transistor, transformer ...) for each manufactores brand, so that schematic for each brand is same.

[vintagekiki]

Helmholtz

[beedoola]

Did you have a plug in the input jack while measuring? Otherwise the jack will short any voltage.
Can your meter measure mV?

If your guitar pots are only scratchy with this amp, I'd expect some DCV.

Thought I replied to this but yes, I measured with a plug in the jack. I do have a MV setting on my DMM. I'll check that out.

I realized my OP said my pots are "crazy" when I meant to type "scratchy." Only with this amp.

It has much improved since cleaning and rebuilding the circuit. I tested the Can cap to see if it was good, if that might be an issued and it is ok.

I also did what others suggested - maybe in another forum, can't remember - and removed the 68k input resistors from the board and put them directly to the jacks.

[Enzo]

About testing caps. If by testing it you mean measured its capacitance with a meter, that is only a very SMALL part of testing. The value of a filter cap is not all that important. Caps have notoriously loose tolerance. In fact way back when, the can caps had typical tolerances of +80/-20%. If a cap should be 20uf but is really 10uf or 30uf, the circuit will still work fine. But your meter measures caps with just one or two volts at most. The main problem with caps is leakage and other factors at operating voltages. What a cap measures at a volt or two may be nothing like it performs at 400 volts.