No sound from my JCM 800 combo. HELP! (Please)

Hi.
A friend gave me a JCM 800 Combo (212, 50 watt, 2 channels). Not sure how old, (early 90's?). It's worked since I got it about a year ago. I haven't really used it much, just in the basement. I use a different amp in my band. The last time I used it, about 2 weeks ago, it sounded fine.

I decided that I would bring it to practice to properly put it to the test, really excited to see how it fit in the mix. I set it up, powered it up, and waited. And waited. There was power going to the amp, (the power light was red). I flipped the stand by switch and there was nothing. No hiss. No "Pop", nothing. I check all the usual. The speakers were plugged in. The fuses looked good. Tried a different cable. The tubes were glowing. Volume was up, both channels and the master. There was absolutely no sound.

My first guess is to try new fuses anyways. I don't have any extra, so it will be a few days before I can do that. I'm not sure that is the answer though, since there was power going into the amp.

The more I think about it, I now know I should plug it into a separate cabinet, to make sure it isn't the speaker connection. I'll definitely do that when I get home tonight.

I'm not pressed for time to get this fixed, as I have a few amps to work with, but I sure would like to be able to use it. I always bring this amp along as my back-up, and would like to continue to do so.

Any ideas?

Thanks!

So, I got home, set the amp up. Power light glows. Still no sound. I plugged it into a 4x12 cab, still no sound. I took out the fuses *again*. They looked fine. I put them back in, switched the stand-by, and......Glorious JCM 800 Crunch! WTF?! :x I can only assume that one of the fuses was loose, and when I put them back in it finally made the connection.

Is there any other possible explanation? I was sure that I had the fuses in tightly yesterday.

What can I say. It's a Marshall. When my friend gave me his Vintage Modern, I didn't realize the "Detail" pot wasn't working properly until the more I fiddled with it and tried to get it dialed in. Then I turned the chassis over and realized the pot itself was loose inside the assembly (not a cold solder) so I took a dart tip and mashed the metal prongs back to hold it tight and *voila* Amp works great now.

There's a reason I switched to Mesa 9 years ago. It's not -just- the tone. It's constant reliability.

But 9 years ago, when I wasn't so savvy, that would have been an $50-80 repair out of my pocket.

SonicProvocateur said:

What can I say. It's a Marshall. When my friend gave me his Vintage Modern, I didn't realize the "Detail" pot wasn't working properly until the more I fiddled with it and tried to get it dialed in. Then I turned the chassis over and realized the pot itself was loose inside the assembly (not a cold solder) so I took a dart tip and mashed the metal prongs back to hold it tight and *voila* Amp works great now.

There's a reason I switched to Mesa 9 years ago. It's not -just- the tone. It's constant reliability.

But 9 years ago, when I wasn't so savvy, that would have been an $50-80 repair out of my pocket.

Click to expand...

You know, you have a point. My main amp is a Lonestar Classic 1x12. Besides sounding great, the **** thing is built like a tank, and has never failed me. In contrast, the knobs on the Marshall feel like they may fall off if I rock too hard, and the first time I was going to use it in a band situation, it crapped out on me. Now, who knows, it's possible that there is nothing wrong with it and something came loose en route to practice. Yet that hasn't happened to me with my other amps.

lance said:

So, I got home, set the amp up. Power light glows. Still no sound. I plugged it into a 4x12 cab, still no sound. I took out the fuses *again*. They looked fine. I put them back in, switched the stand-by, and......Glorious JCM 800 Crunch! WTF?! :x I can only assume that one of the fuses was loose, and when I put them back in it finally made the connection.

Is there any other possible explanation? I was sure that I had the fuses in tightly yesterday.

Click to expand...

Loose or dirty HT fuse or holder.

SonicProvocateur said:

What can I say. It's a Marshall. When my friend gave me his Vintage Modern, I didn't realize the "Detail" pot wasn't working properly until the more I fiddled with it and tried to get it dialed in. Then I turned the chassis over and realized the pot itself was loose inside the assembly (not a cold solder) so I took a dart tip and mashed the metal prongs back to hold it tight and *voila* Amp works great now.

There's a reason I switched to Mesa 9 years ago. It's not -just- the tone. It's constant reliability.

But 9 years ago, when I wasn't so savvy, that would have been an $50-80 repair out of my pocket.

Click to expand...

Yes, but his amp is a JCM800 - one of the best-built and most reliable amps ever made - and not a modern Marshall piece of crap.



They haven't been the same since the JCM900 series. The Jubilees (essentially a late JCM800) were the last good ones.