PROBLEMS!!! MKV..

[richb]

man i turned on my amp without the cab load(by mistake) and blew a fuse.
changed the fuse plugged in the cab and blew another fuse and another and another and...
WTF!!! I checked the power tubes/changed them and still another fuse blown!
anyone???
Thx,
Richb

 

[screamingdaisy]

Call your nearest Mesa repair facility.

 

[domct203]

Does it blow the fuse as soon as the power is turned on, or when you switch out of standby?

If it happens as soon as you turn on the power, you may have a bad Rectifier tube. Put the amp in 90W all channels, remove the 5U4GB and see if the amp will power up. If yes, replace the Rectifier tube ASAP.

If not,

Call your nearest Mesa repair facility.

Even if swapping out the 5U4GB gets the amp running again, I would still have it checked. You could have a blown screen grid resistor or other failed parts that will damage the amp in the long run.

Dom

 

[richb]

Does it blow the fuse as soon as the power is turned on, or when you switch out of standby?

If it happens as soon as you turn on the power, you may have a bad Rectifier tube. Put the amp in 90W all channels, remove the 5U4GB and see if the amp will power up. If yes, replace the Rectifier tube ASAP.

If not,

Call your nearest Mesa repair facility.

Even if swapping out the 5U4GB gets the amp running again, I would still have it checked. You could have a blown screen grid resistor or other failed parts that will damage the amp in the long run.

Dom

cool Dom.
so i called Mesa and chris said the same thing as far as taking out my Rectifier tube and putting all ch's in 90w as well.
let me ask you.if it is the recto tube and i do change it and the amp works what are the chances of having a damaged screen grid resistor or different pt's that maybe faulty?
thx,
Richb

 

[domct203]

let me ask you.if it is the recto tube and i do change it and the amp works what are the chances of having a damaged screen grid resistor or different pt's that maybe faulty?
thx,
Richb

It's hard to say, really. If it is now a bad 5U4GB, we still don't know if that is the cause of the failure, or the result of something else that failed, maybe a power tube. If a power tube did fail it may have taken a screen grid resistor out, as well as the 5U4GB.

Is there anywhere around you that can check the old powertubes? If all four are good, chances are the 5U4GB was the weakest link and everything else with the amp is fine.

Also, if you can, or if you know someone that can, check the bias of all 4 new powertubes in the amp. If one of the tubes shows zero idle current (no bias) then there is most likely a blown screen grid resistor in that socket. They are an inexpensive fix.

Good luck,
Dom

 

[pilgrimx]

I had a similar occurrence with my LSC--never had any problems with the V, knock on wood--and it was a power tube. Fuse blew, fuse blew, fuse blew, changed tubes, problem solved. If you have a set laying around that you know work, and I'll bet you do, I'd drop them in and see. The rectifier tube in my LS was fine. Either way, I hope its an easy fix...
Good luck.

 

[richb]

I had a similar occurrence with my LSC--never had any problems with the V, knock on wood--and it was a power tube. Fuse blew, fuse blew, fuse blew, changed tubes, problem solved. If you have a set laying around that you know work, and I'll bet you do, I'd drop them in and see. The rectifier tube in my LS was fine. Either way, I hope its an easy fix...
Good luck.

actually i don't have a set in the house.i gave a quad set of =C='s to a good friend to check out.
i'll run down to Rudy's and pick some up.
I did have the same problem with my IIC+ and yeah it was a power tube.once i changed it,it never gave me another problem again.
Richb

 

[scoden]

I had a rectifier tube blow on me and I really didnt feel like taking it in to have to see if I blew the screens.( which is always possible when a tube (esp power tube) blows. If you have a multi meter ...you can drop the chasis and check the resistors to see if they still are in spec....if they are you should be fine.

I would only do that if you are comfortable working inside an amp without shocking yourself and can look up the positions and spec of the screen resistors for the amp.....I forgot where I got the info but it was all available online.

 

[richb]

I had a rectifier tube blow on me and I really didnt feel like taking it in to have to see if I blew the screens.( which is always possible when a tube (esp power tube) blows. If you have a multi meter ...you can drop the chasis and check the resistors to see if they still are in spec....if they are you should be fine.

I would only do that if you are comfortable working inside an amp without shocking yourself and can look up the positions and spec of the screen resistors for the amp.....I forgot where I got the info but it was all available online.

I wish i was that do to do that sort of stuff.
it took me years before even changing out a power tube.lol
i have my fingers crossed hoping all will be ok once i swap out all the power tubes and recto tube.
but thanks,
Richb

 

[Anonymous]

FYI http://mesaboogie.com/news/2010/11/mesa-amplifier-tube-troubleshooting/

:wink:

 

[richb]

thanks for that video.however i noticed they never mentioned the fact that a blown tube can blow a screen grid resistor???
not sure what to think now..
Richb

 

[Anonymous]

thanks for that video.however i noticed they never mentioned the fact that a blown tube can blow a screen grid resistor???
not sure what to think now..
Richb

If you have tried everything from the video troubleshooting and the problem persist, take the amp to your nearest authorized mesa repair shop, i mean you still are under WARRANTY.

good luck

 

[richb]

thanks for that video.however i noticed they never mentioned the fact that a blown tube can blow a screen grid resistor???
not sure what to think now..
Richb

If you have tried everything from the video troubleshooting and the problem persist, take the amp to your nearest authorized mesa repair shop, i mean you still are under WARRANTY.

good luck

no need,it was a bad Rectifier tube(thats all).the video helped me out for sure.(thx again for posting it)
I went down to my 2nd home Rudy's music stop in NYC(helps i only live 20 min's from there)..sounds amazing all over again and it's only been down for 3 days,i had it cranked up!!! :mrgreen:
Richb