Mesa 2:90 Problems

[ttosh]

I have had the power amp about a week, bought new from Mesa Hollywood so worst case scenario I can send back under warranty. Wanted to see if anybody could give me some troubleshooting tips.

Tonight when plugging in Channel A had no sound at all and Channel B sounded less than stellar, fizzy kind of. I checked the power tubes, swapped them out of Channel A to Channel B with same results. With Channel B turned all the way down and Channel A all the way up tapped lightly on each tube, nothing total silence, not even hum or hiss that usually is there.

I am going to contact Mesa Service on Monday, any ideas or other things I can try until then?

 

[glip22]

I know this is minimal, but I had a problem with a 1980 JMP I got yesterday. I cleaned it up, lubed everything up. Checked the plate volts and biased it up with a new pair of GTE34Ls. I t rocked. Well today all of a sudden I blew the HT. Found it to be a loose input jack. It was doing exactly like yours was. I only blew the HT after I turned it up to 11. Check your PI tube also. You didn't post you checked your pre tubes, although that's probably where you went first. Good luck. The only amp I have never had any problem with is my Cornford MK50H.

 

[FUZZboat]

hey man

only thing I can suggest is be careful !!


I have a peavey ultra 120 sitting on my bench that I got off ebay
cheap with the problem stated by the seller "power amp section works great but no preamp sound."


after pulling it apart and measuring plate, grid, cathode etc voltages
I was very surprised to find 678 VDC on 2 of the power amp tube sockets (and these were'nt the plate pins !) - one wrong move and that shit will stop your heart in an instant !!

 

[ttosh]

Yeah I looked at the pre tubes first, they looked great, the fuse looks great and the power tubes swapped channel b still works and nothing from channel A.

Fuzz I hear you, I do not go much further than just checking tubes, and I stay away from it as much as I can.

Since she is only 2 weeks old I am going to let Boogie support take care of it. Hopefully they will turn it back around quickly for me as it sucks having stuff that is not working....

/rant

 

[killertone]

I had a 2:90 in my live rig for about a year. Loved the tone of it but after a few load ins and load outs, the power tubes would work themselves out of the sockets and a couple of them arced on me one night. That seriously sucked. That is my only complaint about that amp.

Hope you get yours fixed quick. It is a good thing you can go back to Mesa and get it dealt with. They should just swap you out a new one, IMO.