Thanks for all the detailed information. I get the picture now how to trace the signal through the pre-amp. I ordered some hook-probes on Ebay, and are going to connect them to an 'old' guitarcable.
I'm going to try fixing the amp the next couple of weeks I think. I let you know the results here.
Thanks for all your help, I appreciate it very much.  :dbtu:

Adrie

Quote from: J M Fahey on April 20, 2015, 10:35:42 PM
One detail: were you injecting audio at the preamp input, say a friend playing guitar or some CD/MP3 , while you tried 1 and 2?

Just checking.

If no sound still, after setting the controls to sensible values, you'll have to trace audio inside, to check where you lose signal.

Please post schematic .

While testing I used a guitar. I got original schematics from people at Randall itself.

All the parts look alright, nothing 'burnt', no burn-smell. What's the best (simple) way to trace the audio in pre-amp part of the amp?

Adrie

Quote from: J M Fahey on January 27, 2012, 04:18:03 AM
OK.
Do you have Effects/Loop send/return jacks?
If so
1) plug a known good cable from send to return , and your guitar at the input. Do you get normal sound?
2) plug a cable from the send jack into another, working amp. Sound?
3) plug the line/loop/pre out from another amp into your loop return. Sound?
Test these first, I have others to ask you, but let´s go step by step.

And, yes, there was a mixup between posts. Oh well.

My Randall RH100 is not working. I did the tests suggested by M Fahey, and I know now that the power-amp part is allright.
Test 1: no sound.
Test 2: no sound.
Test 3: YES, there was sound.

The guy who gave me this amp told me that the amp acts like a tube-amp. Before it gave no sound at all anymore, the amp made sound after a couple of seconds. What can be the problem? Potmeter with bad contact? Some bad condensator?
I replaced the input-jack already, because it looked worn. But this was not the problem, amp still not working.

Adrie