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Mesa M-Pulse 600 quit on me last night

bthrem

bthrem

Dec 4, 2005
849
98
Cincinnati, OH
www.facebook.com
#1
Had a very strange thing happen to me last night a band practice. About 2 hours in, my (3 or so year old) Mesa M-Pulse 600 stopped producing sound. There was no hiss, etc coming out of the speaker jacks. The only audio I could get to come out was from the tuner out and the DI in pre mode (post mode produced no audio). There was no warning or odd noises before output ceased, and the amp was barely warm to the touch. The amp is racked in the middle spaces of a 4 space rack with only a tuner on top and nothing below – should be plenty of ventilation. I turned it off and on a few time to see if that would cure it, but no go. Just fired it up this AM and it comes right on again. Could the pre-amp tubes be wearing down and becoming intermittent? I’m going to leave it on all day (and night if need be) to see if I can get it to fail again. Anybody else have this happen?
 
#3
I think it only has 2. But yes, that's the obvious place to start.

I was really hoping to plug it in this morning and have it still not working. Intermittent issues are the toughest of all to troubleshoot. Fortunately I still have a few years left on the warrenty if something more ominous is wrong.

Matt, hope you can make it to the Cincy GTG on 3/21. Would like to meet you finally in person!
 
#6
Seems to be a rash of this going on... anyway, I'm going to quote KJung's helpful response to my postings on mesa weirdness when my M-Pulse 600 went out during a rehearsal:

Along with the tubes, this symptom (although typically not that extreme) can also be caused by a problem with the effects loop jacks. Try plugging and unplugging a cable in the send and return jacks a few times to see if that has any impact on the problem. I can't remember exactly why this is, but it has something to do with 'jumper's getting stuck open on occasion in the effects loop if you haven't used it (i.e., inserted a cable) for a while. If you have an older model with the separate active/passive inputs, they can also cause a similar problem (the newer models have a single input and an active/passive switch). If you have the dual input model, again, try plugging and unplugging a cable from the jack you don't typically use.
Click to expand...
 
#8
I have an mpulse bass amp and a mesa boogie .50 cal+ guitar amp.
the guitar amp was doing something similar and I called mesa...
ended up running a short patch cable from the effects send to the effects return and problem was solved?
 

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