Mesa 2:90 need a new power switch.

[JeffHenneman]

I have a mesa 2:90 that needs a new power switch. At first my switch was acting funny, like staying on in the off position and then would not go on untill I flipped it back and fourth. Then it started working normally for a while then I started smelling something burning. So when I opened the amp up and turned it on I noticed the switch smokeing. It does not have any marking on the toggle switch, do any of you now what kinda switch I need to get? I got one from radio shack but when I hooked it up it started smokeing, so I think I fried that one.

 

[ando]

I have a mesa 2:90 that needs a new power switch. At first my switch was acting funny, like staying on in the off position and then would not go on untill I flipped it back and fourth. Then it started working normally for a while then I started smelling something burning. So when I opened the amp up and turned it on I noticed the switch smokeing. It does not have any marking on the toggle switch, do any of you now what kinda switch I need to get? I got one from radio shack but when I hooked it up it started smokeing, so I think I fried that one.

First you need to know what voltage is at the switch. You can test that with a multimeter (be careful!), then just make sure the switch you buy has a decent current rating. For a 230V situation, I'd get a switch of about 10 Amps. For a 120V application, a bit higher - up to 20 amps may be necessary. That will be overkill but it's good to have a safety margin. If you know how to use an ammeter, you could actually run the amplifier with the ammeter in place of the switch - then you would have an accurate idea of what your switch needs to handle. If you don't have this sort of gear or the skill to use it, either buy a really oversized switch and try it out, or get somebody qualified to do it. It's not worth risking if you are not experienced with handling high voltages.

 

[JeffHenneman]

Thanks for the quick reply. The switch I got was a 30 amp switch, I thought it was over kill but it started smoking once I engaged it. I am a little lost, on this one.

 

[ando]

Thanks for the quick reply. The switch I got was a 30 amp switch, I thought it was over kill but it started smoking once I engaged it. I am a little lost, on this one.

That points to a further problem with the amp, I'm afraid. You shouldn't be able to fry a 30 amp switch (assuming the voltage is 120V) . If you are, you are very close to frying the wires that supply the switch and most likely something has already burned or shorted out. Possibly the power transformer, I'm not sure because I never studied the circuitry of a 2:90 (even though I have one). I think you will need to get the amp looked at because messing around with things further may cost you a lot more than you can save.

Good luck with it all.

 

[JeffHenneman]

Thanks for the help, I found a switch in my tool box that was 125v 10amps, I hooked it up and everything worked fine. Thank goodness for extra spare parts. I am gonna have to go back to electronic store I got my switch from and let them know there might be something wrong with those switches.

 

[ando]

Thanks for the help, I found a switch in my tool box that was 125v 10amps, I hooked it up and everything worked fine. Thank goodness for extra spare parts. I am gonna have to go back to electronic store I got my switch from and let them know there might be something wrong with those switches.

That's very strange indeed. I don't think I've ever had a brand new switch fail on me like. I guess you got lucky that it was so simple.