on my last leg. blowing fuses

[pennman]

soooo, i swaped the 6v6s in my mb for the el-34's which were3 in it before. never had problems with them before, but low and behold, as soon as the standby switch was flipped, the fuse popped. so i put the 6v6s back in, popped again. bought brand new 6l6s, popped again. any thoughts? could it be a screen? I dont feel right when my amp doesnt feel right and i miss that sweet sound already.

 

[topcat0399]

soooo, i swaped the 6v6s in my mb for the el-34's which were3 in it before. never had problems with them before, but low and behold, as soon as the standby switch was flipped, the fuse popped. so i put the 6v6s back in, popped again. bought brand new 6l6s, popped again. any thoughts? could it be a screen? I dont feel right when my amp doesnt feel right and i miss that sweet sound already.

dude, something shorted - take it in.

 

[Tweeked]

Call Mesa they will help you.
Usually it's a tube problem,on mine when the rectifier tube
blew it took part of the tube socket with it.Went through a lot of fuses!
They helped me troubleshoot over the phone.
Still had to take it in but they were a huge help with my
amp which is still running perfectly to this day.

 

[cscotto]

Go to Mesa's website look at the tube video in the trouble shooting area. The video gives you several techniques for testing the exact problem you are having. Basically, if you take out all the tunpbes and flipping the standby switch blows the fuse, it is not a tube. If the amp stays on, then it is a tube. You put one tube back and repeat the test until you find the bad tube. Watch the video. HTH

 

[94Tremoverb]

It doesn't sound like a tube, if it blew the fuse with several different sets - highly unlikely they're *all* faulty.

The most likely cause is an arced/carbonised power tube socket, as Tweeked said - although it could be a few other things.

Do *not* remove *all* the tubes and power up! If you do that, you may blow the filter caps at the preamp end of the supply chain - you must leave the preamp tubes in to create the necessary current draw that will reduce the voltage down the chain. The preamp tubes won't be the cause anyway. (Although it could possibly be the reverb driver tube, which is actually being used as a small power tube - but still not very likely.) It *is* safe to remove all the power tubes, and rectifier tubes if the amp has them - though normally a failed rectifier will blow the fuse on power-up, not coming off standby. If the amp has rectifier tubes, put these back in and test the amp before you put the power tubes in.

 

[cscotto]

Thanks 94tverb. I should have been more specific. You are correct. In the video, the test shows only power and rectifier tubes being removed. After reading the op a little more carefully, you are also correct that it is probably not tubes since different sets caused the same problem.

 

[pennman]

thanks for your help everyone. After running diagnostic i found that the problem was a failed rect. tube, no idea why it only blew when taken off of standby. murphys law i suppose.

 

[topcat0399]

thanks for your help everyone. After running diagnostic i found that the problem was a failed rect. tube, no idea why it only blew when taken off of standby. murphys law i suppose.

whew!

 

[Tweeked]

Tube problems are so annoying.
Glad it was an ez fix.