Help me bring back to life an old Peavey Rage 108 guitar amp!

[JMFahey]

Hi, I know that this is a super necro-bump of this 10-year-old thread, but I'm working on a Peavey Rage 108 and I'm getting exactly the same symptoms as the OP in this thread. Unfortunately, it looks like they never returned to this thread to report if anything worked to fix it. When I turn on the amp I get a really harsh, square-wave hum (you can hear harmonics in the hum). I followed the advice in this thread and tested it by jumpering the treble control, which didn't fix the hum but now made the bass control interact with it. I ordered a new power amp chip and just finished replacing it and sadly the amp is still humming exactly the same way.

Thoughts?

Suggest you open a new thread, with YOUR amp pictures, etc.

And no, it´s HARDLY EVER the exact same symptoms, besides "not working" ; all18 posts previous to yours do NOT apply and do NOT help, only confuse.

Only useful data is schematic, which you can link to.


Start with a couple sharp well illuminated closeup pictures of YOUR amp. showing supply, chipamp, etc.

 

[Poparad]

Welcome.



Main power capacitor(s)????

I don't know why people replace tubes/chips for simple DC-filter rot. Tubes/chips don't know how to hum, only reproduce hum fed to them. At the input, OR through the power lead.

Thanks! That seems the next likely culprit and a pretty easy fix. I'll have to order some new caps as I only have much smaller ones for pedal circuits. I'll also double-check the leads to the transformer as something may have happened when I was pulling the board out to work on it. I'll be sure to report back my findings!

 

[Poparad]

Suggest you open a new thread, with YOUR amp pictures, etc.

And no, it´s HARDLY EVER the exact same symptoms, besides "not working" ; all18 posts previous to yours do NOT apply and do NOT help, only confuse.

Only useful data is schematic, which you can link to.


Start with a couple sharp well illuminated closeup pictures of YOUR amp. showing supply, chipamp, etc.

Well, in this case it was the exact same symptoms: loud, continuous hum that was affected only by the treble pot, no signal at all passing from the input and all other pots and switches (including level) had zero impact on the hum. The OP's description fit mine to a 'T.' I decided to reply here because when doing a Google search for possible solutions, this thread comes up at the top of the search results. I figured if I could find a solution here, it would help other people in the future and they would be able to find it more easily in the top-ranking search result.

 

[JMFahey]

YOU think it´s the "exact same" symptom.

FWIW there´s 5-10 different possible causes for it, even if it "sounds" the same.

That´s why Techs troubleshoot broken amps instead of throwing parts at it at random.

AGAIN: open a new thread, with YOUR pictures.

Example: 10 people visit a Doctor, they all complain of a "splitting headache" ... do you think the Doctor will assume they all have the same problem?
That he will check one and give same medicine/treatment to all 10?
Think again.

 

[Poparad]

YOU think it´s the "exact same" symptom.

FWIW there´s 5-10 different possible causes for it, even if it "sounds" the same.

That´s why Techs troubleshoot broken amps instead of throwing parts at it at random.

AGAIN: open a new thread, with YOUR pictures.

Example: 10 people visit a Doctor, they all complain of a "splitting headache" ... do you think the Doctor will assume they all have the same problem?
That he will check one and give same medicine/treatment to all 10?
Think again.

Thank you for your reply, but please dial down the condescending tone. I just joined this forum and this is really unwelcoming behavior. I came here to hopefully share some knowledge and help others and learn something myself about audio electronics in the process. I will continue to put forth as positive a contribution as I can and I would respectfully ask the same in return.