Last night mid song my amp just ate shit, completely cut off. When I switched the power off and on again it came on for a second made a loud humming noise and shut down. When it's on standby it would power up and stay on, then when engaged hum and shut down. It only did that twice now it doesn't work at all. There was no smoke or burning smells just silence. Is anyone hear familiar with these amps or these problems?

Check your power amp tubes(since you don't have pre-amp tubes)
Check and see if there is an internal fuse for the output transformer, could be burnt.
Make sure all your input solder joints are intact.
Those amps are pretty bullet-proof, worst case scenario is that you have a blown output transformer, they couldn't be more than $200-300.

thats another thing, i don't think my tubes where lighting up but couldn't tell because it was cutting off so fast. thanks for the info.

If the amp makes a humming sound, then the tubes are lighting up and if there's a fuse for the OT it's not blown. If either of the tubes weren't lighting up or an OT fuse was blown, you'd get no sound at all.

It sounds like a bad output tube, maybe something like a shorted element. Throw the tubes on a tester and you'll probably find that one is bad. That's my guess anyway.

Thanks scott, I really hope thats all thats wrong with it. I've got a friend looking at it for me this weekend........fingers crossed.

Out of curiosity, what model are you using? I don't run into too many other Music Man users. Mine's a 112-RD.

HD-130, and I love that big bastard!

0K CYB0RG wrote:...I don't run into too many other Music Man users.

My guitar player uses a 112 Sixty-Five. Fat Bobby from Oneida uses two MM combo amps. Emandee studio in Brooklyn has two or three MM amps in constant use. My friend Dan used a 210 One hundred-Thirty for many years before switching to a Marshall combo. It seemed for a while everybody was using these amps...

They are great amps.

Could also be a bad tube socket or a broken lead somewhere.

jmartin7221 wrote:Last night mid song my amp just ate shit, completely cut off. When I switched the power off and on again it came on for a second made a loud humming noise and shut down. When it's on standby it would power up and stay on, then when engaged hum and shut down. It only did that twice now it doesn't work at all. There was no smoke or burning smells just silence. Is anyone hear familiar with these amps or these problems?

OK. Does this amp have a driver tube? That would be a small tube just next to the outputs. If so then then check the output tubes and the power supply - especially the rectifier diodes.

If your amp has no driver tube, which is more likely, then it has driver transistors. These blow all the time and cause the amp to take a fast dive. The original transistors may be hard to find but places like Mojo may have good substitutes. I understand the 2N6488 is a good sub but you must replace all of them (verify the pinouts) and then re-bias.

The chances of you loosing a transformer are very slim. MM used great xfmrs in their amps.

yeah it's the older model with the tube rectifier. thanks for all the help guys seriously.