What to do with this Mesa Maverick?

[Randall]

This thing buzzes, more in the rhythm channel than in the lead, has relay chatter on power on, and loses power at random times. The owner changed every tube, no change. I spot a .047 cap with a hole burnt in it, so I replace it topside, no change. Not that I even know what it's job is, neither the pcb nor the schematic has component designations, only values. There is no way to get under the board without lots of time consuming disassembly/reassembly. I have clipped caps across every filter cap, no change. The FX jacks are not switching cutout jacks, so it's not there.

I am about an inch away from calling the guy and saying sorry, but I can't help you with this one. It almost seems as if Mesa doesn't want you to be able to fix this amp. The chassis is folded in on the sides 1'', the pcb is tucked under the folded part fully on the left side and just a little on the right. It looks as if there is only one way to get it out, and you'd have to either disconnect or unfasten every control, jack and switch front and back to do it, including the power tube board.

GRRR.... I freaking hate these amps.

[alexradium]

you got the point,the company doesn't want anybody other than the "authorized" repair guy to put hands on their amps.
It is time consuming,because they didn't think about serviceability.
I'd say its probably some soldering gone cracking underside,and some cap or transistor failing.

[nosaj]

This thing buzzes, more in the rhythm channel than in the lead, has relay chatter on power on, and loses power at random times. The owner changed every tube, no change. I spot a .047 cap with a hole burnt in it, so I replace it topside, no change. Not that I even know what it's job is, neither the pcb nor the schematic has component designations, only values. There is no way to get under the board without lots of time consuming disassembly/reassembly. I have clipped caps across every filter cap, no change. The FX jacks are not switching cutout jacks, so it's not there.

I am about an inch away from calling the guy and saying sorry, but I can't help you with this one. It almost seems as if Mesa doesn't want you to be able to fix this amp. The chassis is folded in on the sides 1'', the pcb is tucked under the folded part fully on the left side and just a little on the right. It looks as if there is only one way to get it out, and you'd have to either disconnect or unfasten every control, jack and switch front and back to do it, including the power tube board.

GRRR.... I freaking hate these amps.

You can check with lowell he's an authorized Mesa rep but I don't think he likes them any more than you do.

nosaj

[Justin Thomas]

Alexradium,

That thumbs-down is not at your comment, but at Messa Booger's construction techniques.
Never have I seen such expensive amps worthy of being considered worthy of "do not repair" status.

OTOH, there MUST be some sort of trick to these things, we just don't know it.

Justin

[Randall]

"OTOH, there MUST be some sort of trick to these things, we just don't know it."

Exactly. I suspect there may be extra/other documentation available to the authorized shops, and maybe some helpful hints from the factory guys. How are we supposed to service an amp that will take an hour just to get the board out/in, and risk causing further problems by flexing all those connections on wires that haven't moved in 25 years, while looking at a half assed schematic with no component numbers, and a pcb with just values printed under the components where you can't see?

[drewl]

Check the four 1N4007 diodes they use for the DC filament voltage to the preamp tubes which is also used for the low voltage supplies for switching etc.

Hell, just replace them.
They are old and failing, will burn the PC board and cause this problem.

[Jazz P Bass]

Some pretty good shots here of the octopus PCB: http://trentstuff.com/1993-Mesa-Boog...Mesa-Pics.html

[nosaj]

Some pretty good shots here of the octopus PCB: http://trentstuff.com/1993-Mesa-Boog...Mesa-Pics.html

Doesn't look any worse than say a prosonic PCB to me. I expected something like the Peavey 30 with the folded boards.


nosaj

[Randall]

That chassis and layout is not the same as the one I have. That one looks to be at least 2 inches longer on both sides. This chassis is 17" wide, the board is a tad over 16" This pcb is jammed up right to the side of the chassis under the folded in lip on one side, and not quite as far in on the other. All the wiring is packed in and around things to facilitate that. That one doesn't look too too bad, this one looks like the equivalent of certain cars where you have to pull the motor mounts to change the filter.

[Simpson]

I once had a problem caused by the LDR that was introducing noise in one channel. It was not on same model but i would try and check it.

[Chuck H]

This thing buzzes, more in the rhythm channel than in the lead, has relay chatter on power on, and loses power at random times.

The constraints of actually being able to perform the work not withstanding,.. Do you mean to say that the amp actually loses power or that the amp loses output signal?

[Randall]

"Do you mean to say that the amp actually loses power or that the amp loses output signal?"

I don't really know, the customer is vague, but I think he means a drop in loudness.