Valvestate 65r

[C Moore]

Working on a friends (his son) amp. He said it started to "Hum" just recently.

1. Is it Reliable/Accurate to use the Hz setting on a Multi Meter to measure the noise.?
If i hook my meter to the speaker wires, and it says 120, does that mean the problem IS indeed 120 and not 60Hz.?

2. Right near the power tranny are four parts...two small Caps C-11 and C24...and two diodes ZD-1 and ZD-2. These show signs of getting pretty Warm/Hot, but i doubt i can test them in circuit.?

I have Chopsticked all over the amp, and nothing has an effect. There is One 12AX7 in this amp. I replaced that with no improvement.
The hum is not effected by the volume knobs and is present with or without a guitar plugged in. The hum is present on Both Channels.
Does this sound like a typical Power Supply/Filter Caps kind of a problem.?
Thank You

Schem -
http://el34world.com/charts/Schematics/ ... 5r_65w.pdf

[Stevem]

If the amp is playing, but humming then I would change out C11 and C12, the 2200 uf 50 somthing volt filters as those are likley going bad.

Actually I just noticed that right after those two caps are two 2.2 uf caps rated a 63 volts so in replacing those 2200 uf filter caps I would get new one in a voltage higher then the stock 50 volts if you can find ones that will fit?

[C Moore]

Thank You.....i will give that a shot.

[C Moore]

Well, i have got the new caps in...and the Mains Fuse (F2) snaps immediately.!
I know its Possible "something else" went wrong.....bit i suppose i should pull the boards, and see if a did not create a short somehow. Maybe a little solder blob or whisker is shorting something.?

I drew a nice map that shows the colors and numbers of where the wires go. I am as sure as a person can be that it is all back together correctly...and i doubled checked it.
The caps are in the right way. The short leg of the radial is negative, and so is the Silver Stripe on the cap. They went in the way the old caps came out.
I must have done something stupid or created a small short somewhere.

[C Moore]

I am not used to working on PCB amps, or worrying too much about flux residue. I had a small bridge from one trace to another and it was hiding under some flux.
Anyway.....this still hums really bad.
I have just a basic knowledge of tube amps and really know nothing about Solid State stuff.
Do transistors get "Noisy" or do they usually just fail.?
Thank You