Help! My F50 stopped working!!

[ericlingus]

Hello all. Unfortunately my amp just all of a sudden shut off and stopped wokring. First it turned off and then back on quickly. I then turned it off and then back on and there was a delay from the time I flippe dthe switch to when it turned on. It turned off shortly after though. I tried switching out the power tubes for my old pair that still worked fine but it did nothing. I havent done anything to it since then. Maybe it just over heated and needs to cool down? The only thing new that has happened to it recently is a new cab that I got for it. I have a 212 genz benz now that I hook it up to. I have it going from the mono 16 ohms out jack to the 8 ohms in jack of the mesa. I was told this was safe to do. It's been like this for almost a month now with no problems so it seems like it would have acted up sooner if that was a problem.

I have had it for almost two years now with no problems. I always warm it up before turning it on all the way(I leave it in standby for a minute or so) and when I turn it off I always make sure to put it in standby again for a minute or so. I have been using it a lot lately. I had it on today for about 5 hours. I was recording with it. It's in a cool room and the amp has plenty of ventilation. Does anyone know what this might be? I bought it used from guitar center close to two years ago so there is no warranty. Is there anything I can do to get it fixed for free or am I going to have to pay? If so, where do I bring it to get it fixed? Does guitar center do this or do I have to ship it somewhere to mesa? I appreciate any feedback. Thanks

 

[Charlie]

Does the amp turn on at all? Does the light on the front of the amp come on? Are any of the tube filaments glowing?

You didn't really specify if the amp is totally dead or not. Might just be a bad preamp tube or a fuse.

I'd try switching the fuse out for a new one first.

If the amp is totally dead it probably isn't a preamp tube though.

 

[ericlingus]

that amp does not turn on at all except the footswitch...the light does not turn on on the amp, only the footswitch.

 

[Charlie]

Try changing the fuse and leave the new set of power tubes you installed in there. The old set may been on the way out and blew the fuse.

Make sure the new fuse is the correct rating.

 

[ericlingus]

no. The amp died before I switched tubes. I had the new tubes in already when the amp died. I switched them out after the amp died to see if it was the power tubes. Or were you talking about when I get a new fuse to make sure the new tubes are back in in case the old ones die and blow the new fuse?

 

[Charlie]

The amp died before I switched tubes. I had the new tubes in already when the amp died.

Maybe it's too late at night for me but these two sentences seem to completely contradict each other.

Point I was trying to make was that you should make sure you have good tubes in when you replace the fuse.

I'm *guessing* that maybe one of your power tubes went bad and took the fuse out.

You can just take the fuse out and look at it and you *should* be able to see if it's blown. Even if it doesn't look blown it's probably worth it to try replacing it anyway and see what happens.

Good luck.

 

[ericlingus]

im just saying that I had new tubes in when the amp broke. I had replaced them a few weeks prior to that. After the amp broke I switched them out for other ones which were older but still fine to see if it was the power tubes causing the amp to not work. Before I try a new fuse i'll make sure to put the newer ones back in. Thanks a lot for your help. Much appreciated.

 

[nemesys]

The new tubes may have been defective, and shorted after a few weeks. When you try the new fuse, put known-working tubes in too. If you got your new set of tubes from Mesa, give them a call -- there's a six-month warranty on them, they'll probably send you a replacement set.

 

[AdmiralB]

If the footswitch is lighting up, it's not the fuse.

 

[ericlingus]

I checked again and the footswitch is not lighting up. I just did it when the amp first died. I see the power tubes lit up when I turn the amp on but nothing else.

 

[domct203]

that amp does not turn on at all except the footswitch...the light does not turn on on the amp, only the footswitch.

Agreed, if the footswitch lights up, it's not the fuse. I'm not sure if the power transformer could fail on the high voltage taps only.

When you say it does not work, is it just that the pilot light does not come on, or have you confirmed that there is no sound? Could it just be a dead pilot light bulb?

If there is no sound, have you tried a different instrument cable and or guitar?

Also, is there any kind of fuse protection in the speaker cabinet?
Have you tried a different speaker cable? I would check that anyway because if the speaker cable has a break in it, you are running the amp with no load when you trouble shooting.

Good luck,
Dom

 

[domct203]

I checked again and the footswitch is not lighting up. I just did it when the amp first died. I see the power tubes lit up when I turn the amp on but nothing else.

Hmm, When you switch out of standby do you see a blue glow come on inside the power tubes? If not, maybe it's just a bad standby switch.

Dom

 

[ericlingus]

yeah a blue light does come on

 

[domct203]

Have you tested the guitar and guitar cable to make sure they are good?

Dom

 

[ericlingus]

yep my guitar works fine. I'll re test all the cables. Although i'm sure they are fine as well because when the amp turns on it makes no noise at all. Usually it makes a "turning on noise". Do you have any other ideas of what it could be? Is it possible it could be the pre amp tubes or would the amp light still turn on if any tubes were bad?

 

[ericlingus]

hmm I tried turning it on again and when I turn the volume up I can hear some crackling from the amp. It's very quiet. It also does still make that "turning on noise". The clean channel is what it seems to stay on because when I turn the volume up on it the crackling gets louder. When I try to switch it over to the other channel, first with the footswitch then on the amp itself, it seems to do nothing because the clean channel volume still controls the crackling and not the other channel.

 

[domct203]

Call Mesa and talk to a tech. Describe the problems you are having and see if they can help.

The crackling could be a pre-amp tube(s), But the loss of channel switching and no other lights on the amp points to something more.

The amp will normally default to ch 1. When you tried changing channels with the amp's selector, was the footswitch unplugged from the amp?

And are you trying the amp with the FX loop Hard Bypassed?

Just trying to eliminate as much as possible.

Good luck.

 

[Charlie]

+1 to calling Mesa.

So your power tubes are getting power but the light on the front of the amp does not come on?

 

[ericlingus]

yep

 

[estring]

Trying replacing V4. I had a similar problem. I had lights but no sound.

Let us know!!!