NEED HELP....F50 + Smoke = Bad

[John Denver]

I was playing my F50 last night, when something strange and terrible happened. I had the gain around 9:30 and the master at 12:00 on the contour channel....i was playing when all of a sudden the sound cuts out...i turn on a light and notice a small plume of smoke that "puffed" out of the back of my amp. I quickly turned it off and checked the fuse....it wasn't blown. The power tubes looked fine. What could this be? I had the speaker connected(duh). I also use a compression pedal as a boost....but not too much of a boost. I turned the amp on a little while later to check it out....it works fine....what happened? I am scared to turn it on now....only had it 4 months. PLEASE HELP!!

 

[Brewski]

Are you running your amp with the stock tubes or did you replace them? Could something have come in contact with a hot tube, like your power cord or speaker cord? Go over your amp carefully and look for any burn marks. Something may be too much power. If you are not sure or cannot find anything, you may want to contact Mesa or an authorized Mesa tech to check it out for you.

 

[John Denver]

yeah.....they are the stock tubes....i just found it weird that it smoked and cut out, but then worked fine...i just don't want to cause any more damage....calling mesa shortly......

 

[matty]

ok if it works now that's a good sign

I had(have) a similar problem with my 2x12 roadster

had it sent in for the recall repair. 4 days later
something goes pop, and I have no sound, unless I crank the preamp
I can hear it a little. strange? After a short while making sure all of my chords are working and making sure that it's not a tube problem...pop...and almost like a black dust cloud that smelled of buning electronics..great god I paid over $$$$ and have only had it 5 months!
so I send it in for repair (warranty is great) and 3 weeks later the return bill says

Replaced Burned Screen Resistors and 1 O/P Tubes
Replaced Bad Mute Feature, Tested OK

OK my ***
this thing has issues...
sound yes, too much sound..yes
it buzzes and humms like crazy. at first I thought it was my pedalboard
so I went direct. then I swiched guitars and patch chords. (from rg550 w/ dimarzios to my wolfgang archtop) then I switched to a different outlet and then my monster power conditioner for my home theater. still loud and something inside sounds like its cycling up and down where it used to be constant.

so I guess it's going back once again
hopefully it won't take another 3 weeks

I loved this amp when I got it but now it's just pissing me off.
if/when it gets sorted out I may not hang on to it much longer.

 

[John Denver]

Well, i took my amp in to the tech...... It was a faulty power tube that blew the screen grid resistor. So now the parts are on the way....sweet! One weird thing i discovered was before i took my amp in, the reverb did nothing....i heard the reverb is a bit weak on the F50, so i just chalked it up to that. Well when i took it in i figured i'd have the tech check that out too.....the tank was completely dead, according to him. I don't use reverb really at all, but i thought that was an interesting find. Mesa has sent my tubes and tank.....i'm wondering how in the hell that happened to a new amp. Had it for 4 months.....oh well, i just can't wait to make my baby scream again.

 

[Brewski]

I wonder if possibly your amp got jostled or banged in transit. Which might account for the tank, or maybe it was infant mortality on the tank. It'd be interesting to know if the springs were broken or if it was due to some other issue.

The good news is that Mesa is taking care of it and it's getting fixed.