Problem with Dual Rectifier

[JamesTGP]

Hello,
I've been searching the net and found this forum so was wondering if anyone would be able to give us some advice on a problem we've got with a 1999 two channel Mesa Boogie Dual Rectifier Solo Head.
Basically, when we turn the amp on, the main power light comes on, but when the guitar is plugged in, the channel lights don't come on (like they did before) and no sound comes from the guitar. It is worth noting, however, that the power tubes do seem to be making some sound, as there is definately something coming out of the speaker when the guitar is or is not plugged in (a faint humming, just background noise from the amp we presume).
We were wondering if anyone has any ideas of what it could be / what we could attempt to fix it. We're from the UK and there are very few people who service the amps over here we've found.
Thanks,
James + Chris
The Guilty Pleasures (www.theguiltypleasures.tk)

 

[ZeE]

Sounds like a short of some kind .....

Give Westside Distribution a ring ,,, they are the UK distributors for Mesa

I spoke to a guy called Mark , he was very helpful

0141 248 4812

Hope this helps

 

[Lespaulstandard]

I almost want to say a fuse of some sort.

 

[jbird]

So, if you plug and un-plug the guitar cable, the channel light (whichever channel is selected) goes off and on? Something with the input jack? You are using an instrument cable, correct? Do you have a cable plugged in the channel switching jack, on the front, for your footswitch? Do you have the channel select toggle on the rear in the correct position to use with the footswitch? Does channel switching work? Bypass on the F/X Loop? Nothing else unusual? You may try a search for The Gear Page, it's a very informative site, has a section for Amp Technical Questions, and some very knowledgeable folk! Good Luck and Please let us know!

 

[ChrisTGP]

Hey, I'm the owner of the amp. When we plug the guitar into the input jack, the channel lights DO NOT light up, like they should do. Thus channel switching doesnt work. Basically, it seems like the amp just isnt recognising that we're plugging in the guitar. We've checked the connections on the input socket and its all fine.

 

[jbird]

But they will light up if theres no guitar plugged in? And does channel switching work when theres no guitar plugged in? Are you using the channel switching jack on the front, or manually selecting a channel on the rear toggle? Does it matter? What about a Relay that controls these functions?

 

[JamesTGP]

Sorry, we've been a bit confusing here. The channel lights do not light up at all, whether a guitars plugged in or not. It never really occured to us (or we hadnt noticed) that the channel lights light up when a guitar isn't plugged in, I guess we've never turned it on without a guitar plugged in.

 

[ishoulddie]

i had a similar problem a couple of years ago. The symptoms were the same: power lights came on, but the channel lights did not, and the only sound was a humming from the power tubes. Called Mesa, they said it was a problem with the channel switching mechanism/circuit. Took it into the shop and, sure enough, they were right. Apparently it's a pretty easy fix. So, if you haven't already, take it into the shop. Not much else you can do on your own, unless you have the schematics and can get the parts.....