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Any Guitar Amp gurus?

crank1000

crank1000

Dammit Bobby.
Joined
Apr 7, 2008
Location
East Bay
Moto(s)
2008 Ducati Hypermotard 1100S
So I've got a Mesa Maverick (it's a twist on a dual rectifier). I was jamming on it the other day at a reasonable level (not breaking any windows, but loud enough to compete with a rock drummer). The next day, I go to turn it on, and I get nothing. The light on the front doesn't turn on, and no sound. The main fuse is not blown. I looked at the tubes, and the only tube that heats up is the big main tube. The rest of them are dead/cold. Any thoughts?
 
crank1000 said:
So I've got a Mesa Maverick (it's a twist on a dual rectifier). I was jamming on it the other day at a reasonable level (not breaking any windows, but loud enough to compete with a rock drummer). The next day, I go to turn it on, and I get nothing. The light on the front doesn't turn on, and no sound. The main fuse is not blown. I looked at the tubes, and the only tube that heats up is the big main tube. The rest of them are dead/cold. Any thoughts?
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Did you open it up and look for other fuses? Oftentimes there are fuses not normally reachable...
 
GiorgioFurioso said:
Did you open it up and look for other fuses? Oftentimes there are fuses not normally reachable...
Click to expand...

When you say 'open it up', do you mean drop the amp out of the cab and look at the circuit board? Or just poke around inside the cabinet? I did the latter, but not the former. Are there usually fuses on the actual circuit board?
 
crank1000 said:
When you say 'open it up', do you mean drop the amp out of the cab and look at the circuit board? Or just poke around inside the cabinet? I did the latter, but not the former. Are there usually fuses on the actual circuit board?
Click to expand...

I've seen fuses on circuit boards, but not usually on a tube amp. But it's worth a shot.

edit: I should mention, the last time I saw it, replacing the blown fuse did not fix the problem...the fuse blew to protect other things, but it was caused by a different failure. :(
 
crank1000 said:
When you say 'open it up', do you mean drop the amp out of the cab and look at the circuit board? Or just poke around inside the cabinet? I did the latter, but not the former. Are there usually fuses on the actual circuit board?
Click to expand...

There aren't any fuses on the board and the last thing you want to do is poke around inside an amp if you don't know what your doing. Best thing to do is give Mesa a call and ask them what they think, they're pretty cool about helping out.
 
Ant said:
There aren't any fuses on the board and the last thing you want to do is poke around inside an amp if you don't know what your doing. Best thing to do is give Mesa a call and ask them what they think, they're pretty cool about helping out.
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It's pretty easy getting inside of one. I would hope crank knows about capacitor discharge etc. :dunno
 
did you turn it up to 11?

*edit* damn, beaten out by a minute
 
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Ant said:
There aren't any fuses on the board and the last thing you want to do is poke around inside an amp if you don't know what your doing. Best thing to do is give Mesa a call and ask them what they think, they're pretty cool about helping out.
Click to expand...

I'll give them a call on Monday. Fortunately they're somewhat local, so I can just drop it off if I can't get it sorted myself. I am comfortable getting into some electronics, but tube gear is a little out of my league.

GiorgioFurioso said:
It's pretty easy getting inside of one. I would hope crank knows about capacitor discharge etc. :dunno
Click to expand...

I'm aware of it, and how to avoid it. But if I'm looking at more than replacing surface components, I'll leave it to the pros.
 
IIRC Ogg used to build amps. Shoot him a PM.
 
crank1000 said:
So I've got a Mesa Maverick (it's a twist on a dual rectifier). I was jamming on it the other day at a reasonable level (not breaking any windows, but loud enough to compete with a rock drummer). The next day, I go to turn it on, and I get nothing. The light on the front doesn't turn on, and no sound. The main fuse is not blown. I looked at the tubes, and the only tube that heats up is the big main tube. The rest of them are dead/cold. Any thoughts?
Click to expand...

That amp has both a silicon and tube rectifier, doesn't it? Have you tried switching over to the other rectifier?
 
So the big tube that's still lighting up is likely the rectifier and that's because it's directly heated off a 5V winding from the power transformer. The rest of the tubes being cold says that the 6.3V filament supply is dead, and since they normally run the front panel light off the 6.3V filament supply, it being dead makes sense too.

Soo... either there's a fuse in the filament supply that is blown (I'd have to check a schematic to see if there is one) or the filament winding in the power transformer is toast, or the filament circuit has grounded out somewhere. The B+ circuit (high voltage) could easily still be running, so the inside of the amp is still crazy dangerous - but without filaments, tubes no workie.

I can crack it open and see what's going on with it if you want to drag it over here. I don't have the shop set up so may not be able to fix it, but ought to be able to tell you exactly what's wrong.
 
Ogg said:
So the big tube that's still lighting up is likely the rectifier and that's because it's directly heated off a 5V winding from the power transformer. The rest of the tubes being cold says that the 6.3V filament supply is dead, and since they normally run the front panel light off the 6.3V filament supply, it being dead makes sense too.

Soo... either there's a fuse in the filament supply that is blown (I'd have to check a schematic to see if there is one) or the filament winding in the power transformer is toast, or the filament circuit has grounded out somewhere. The B+ circuit (high voltage) could easily still be running, so the inside of the amp is still crazy dangerous - but without filaments, tubes no workie.

I can crack it open and see what's going on with it if you want to drag it over here. I don't have the shop set up so may not be able to fix it, but ought to be able to tell you exactly what's wrong.
Click to expand...

That is very helpful info Ogg. Thanks. I'll look around for a schematic. That's a lot easier than tearing the amp apart. Thanks for the offer to take a look at it too. It might be just as easy to take it to Mesa though. Fingers crossed there's another fuse...
 
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