Mesa M-Pulse 600 Venture Schematic!

[CJWalker]

I have recently acquired a used Mesa M-Pulse venture 2x10 combo and it seems as if someone had run 48v through the direct out judging from the 2 blown caps on the line output board. However, more problems exist at this point. The power amp section is breaking up at low volumes under load with any speaker cab that I run and I am in need of a schematic so I can finish troubleshooting.

BTW, I didn't realize that Mesa's hours don't include Fridays and I've been anxious to get this thing up and running. Worst case scenario I will see if they will honor a warranty transfer.

Thanks in advance.

 

[KramerBassFan]

I'd just get mesa to do it honestly.

I'm all for repairing stuff yourself, and you seem to be savvy, but, this isn't exactly a Fender Champ.

That said, i've never really looked at one... good luck.
Pics of the guts?

 

[CJWalker]

I'll post some pics up when I go back downstairs. So far the only clipping I see is under any load, pre and post relay from the power amp section measured on a scope. It seems as if it's clipping on the negative side of the wave only. No load, no clipping. Rail voltages are consistent. Honestly, the amp sounds like it's under biased.

If it's something simple I'll take care of it, otherwise I'll see if Mesa will deal with it. I'm hoping they will let me ship the head only, this thing is heavy and built like a tank.

 

[CJWalker]

Sending it out for a bias adjustment.

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