My Mark V isn't powering up.

[joherszch]

Hi guys!

Yesterday when I tried to turn on the amp, the light on the amp illuminated for a second to go off again. I checked the fuse on the back and I saw that it was blown.

So today I went to an electronic store I got a few replacement fuses, however when I switched to a new fuse it blew straight away as the first time.

What else could be wrong and what can I do to get it fixed?

 

[zakkselvagem]

First thing... STOP BLOWING FUSES !! If this is just a tube problem, you could easily fix by changing the tubes. However, dont force it because you may damage something else in your amp by blowing fuses one after another.

Here is a troubleshooting video, I hope it helps.

http://www.youtube.com/watch?v=wSl-l9aWDHw

 

[joherszch]

Thanks for the tip zakkselvagem!

I followed the guide and removed all my rectifier tubes and the same thing happened. New fuse was blown immediately.

I guess I have to contact Mesa Boogie to resolve the problem...

 

[screamingdaisy]

If it's blowing fuses it's probably a failed power tube. I'd replace all four and fire the amp back up. There's a whole troubleshooting section in the back of your manual that explains how to do all this.

 

[Jiveman]

When this happened to me it was a bad rectifier tube. I replaced that and the amp was back to normal.

 

[zakkselvagem]

Usually a fuse doesn't blow out of the blue ... it is generally tube related, that can be easily fixed... but I had a fuse blow one time that I just replaced the fuse and was back to life again, I never new what it was....

 

[joherszch]

It's not a power tube failure.

I've started to think it is a pre amp tube faliure, can I troubleshoot them the same way I did with the power tubes? (Take them out one at a time and turning on the amp?).

Any help/tip is appreciated!

 

[domct203]

It's not a power tube failure.

I've started to think it is a pre amp tube faliure, can I troubleshoot them the same way I did with the power tubes? (Take them out one at a time and turning on the amp?).

Any help/tip is appreciated!

I doubt this is preamp tube related. I have had preamp tubes completely fail (up to loss of vacuum) and never blown a fuse.

If you have removed all power & rectifier tubes and the amp still blows the fuse IMO it is time for a tech. That is even stated in the Mesa troubleshooting video @ 4:55.

Stop stressing the amp with blowing fuses over and over, if you are not sure of something give Mesa a call, they are great to work with and will set you on the right path.

Dom