Reverb for JCM900

[jamie]

I bought a Marshall JCM900 Dual Reverb head about 15 years ago. The reverb stopped working a few years after i got it. The same thing happened to my friends Marshall also.

I want to fix it. Can someone tell me if it is a standard reverb tank(the one with springs inside). Or is it something a bit more complicated like a valve or something.

Havent been here for a while, good to see the board is still up

[UnklMickey]

Yes it uses a typical mechanical spring reverb tank. It also has a hybrid circuit of tubes and solid-state op-amp to drive the tank, and recover the signal from the tank. There's a lot to go wrong there, some of which, you will need some skills to troubleshoot/repair.


cheers,

Unk

[sumgai]

jamie,

Yes, unless you yourself are a qualified repair tech, then it's time to seek out such. You probably didn't know it, but Hammond made/makes at least 8 different models of spring tank, all looking alike. That alone right there means that replacing the tank is not necessarily the easy fix it might be.

Make friends with a techie, it'll pay off in the long run.

HTH


sumgai

[jamie]

Thankyou for your replies.
You are right, i should leave it to someone who knows what they are doing. Unfortunatly i live a long way from cities where a techie could be found. I dont like to leave my equipment in the possession of others.

What i was planning to do is too see if any of the wiring has become loose inside the tank which i have found out is common, since i posted my question.

I might just leave it for now, as i havent used any effects for the last four years. Just thought a little reverb would be nice.
Cheers.

[jamie]

I have been pulling apart the old marshall to re-cover(re-tolex) it. I have stripped the amp down to the bare chasis. I removed the reverb unit and noticed that two wires have shaken loose. I will resolder them and see how that goes.

[jamie]

Finished!!!