My Mesa F-50 is dead...need help!

[Lt_Core]

Hi, this is my first post here at the Boogie Board but I have lurked for awhile. Here is my story. If you have any ideas on what to try I'm all for it. Thanks!

So, here's the short version. Played two nights at the same venue 2 weeks ago for the Packers' opening weekend festivities.

Friday night: 45 minutes into our first set my F-50 starts cutting in and out. After 10 seconds of this it just dies. Luckily I brought a backup amp with me because we were out of town.

Saturday afternoon: played around with the amp for awhile and it seemed fine. Didn't get a chance to turn it up to gig volume, though. Kept it on for at hour or so. No apparent problem. I reseeded the 2 tubes in the back. Fuse looked fine.

Saturday night: halfway through the first song it cuts in and out, then dies. I had the backup amp setup in just in case.

Troubelshooting: I tried some new tubes from Eurotubes just in case it was a tube problem. The new tubes did not fix the problem. I talked to Mesa and they think it's a speaker problem. No sound comes out of the speaker at all, with guitar or no guitar plugged in. Normally I would hear the amp hiss, of course. I am getting power to the amp and the fuse looks good.

I bought this amp on eBay back in June, 2006. The amp was purchased new in March, 2006. I do not have the original receipt, however. Mesa said that's a problem. They did not want my serial number. I live in Wisconsin and the closest Mesa repair shop is 70+ miles away.

Has anyone seen this type of problem with their Mesa amp? Thanks for any help!

 

[Brewski]

I had my F-50 combo at a party gig, plugged it in and flipped the switch, and nothing happened. I had no power at all. Try reseating your power cord into the back into the amp. If you're getting lights but no sound, that would be a different problem.

 

[Lt_Core]

I had my F-50 combo at a party gig, plugged it in and flipped the switch, and nothing happened. I had no power at all. Try reseating your power cord into the back into the amp. If you're getting lights but no sound, that would be a different problem.

Yes, I have tried this and the same problem exists. I have power to the amp but no sound coming from the speaker.

Thanks for the idea. Keep 'em coming.

 

[E_R]

Have you tried hooking it to a diff speaker?
When you were troublesooting the amp, did you accidently flip the speaker mute switch?
Did you change all the tubes (power and preamp)?
Years ago I had a fender bassman head that did the same thing, it turned out to be a preamp tube.

 

[Platypus]

I'd check the tubes in your preamp section

 

[Lt_Core]

I'd check the tubes in your preamp section

I put in a brand new full set of tubes last night. No luck.

 

[Brewski]

Have you tried running your speaker through another amp, just to make sure that all is well there?

I take it that it's dead on all channels, so I wonder if this could possibly a blown transformer.

http://guitar.about.com/gi/dynamic/offsite.htm?site=http%3A%2F%2Fwww.geofex.com%2Fampdbug%2Fampdebug.htm

You may need a tech to help you determine the source of the problem. I hope that it's just a blown speaker or a bad connection somewhere. Well, actually I hope that nothing is wrong with it, but if so, that the problem is the least of all evils. :wink:

 

[Brewski]

Oh, I just thought of one more thing. There is a toggle switch on the back of the amp for silent recording or for using headphones. Make sure that didn't get accidently tripped. I know that it's an outside chance, but I'm trying to think of the simple things.

 

[Lt_Core]

Oh, I just thought of one more thing. There is a toggle switch on the back of the amp for silent recording or for using headphones. Make sure that didn't get accidently tripped. I know that it's an outside chance, but I'm trying to think of the simple things.

Good idea but, alas, it's set for speakers on. Going to take it to an amp tech tomorrow at lunch.

 

[Brewski]

Well, I gave it my best shot. Best of luck with it!

 

[Platypus]

Good luck, let us know how it goes!

 

[disassembled]

Try hitting it with a closed fist on top. Maybe there is a bad solder joint inside. Also, try plugging a cable from the effects send and return incase the jacks got a little dirty. If those don't restore sound you probably need to get it looked at.

 

[Lt_Core]

Try hitting it with a closed fist on top. Maybe there is a bad solder joint inside. Also, try plugging a cable from the effects send and return incase the jacks got a little dirty. If those don't restore sound you probably need to get it looked at.

What does plugging a cable from the send to the return do? I don't quite get that one.

I appreciate all of the help!

 

[disassembled]

If you have a series effects loop it can make all of the difference in the world. If you have a parallel loop don't worry about it. Series loops will cut the signal out completely if the return jack gets dirty. This is a common fix for most amps with serial loops that just cut out or have extremely low volume.

 

[Lt_Core]

The F-50 has a parallel loop. Thanks for explaining that, though.

 

[hal9000]

The F-50 has a parallel loop. Thanks for explaining that, though.

When you had the Mesa tubes in the amp, did the 6L6s glow blue on the outer edge with Standby off (sound coming from speakers)? If so, or if the current tubes show that high voltage is applied, you should be able to tell if the output section is muted. If everything is running normal on my F-100, all four 6L6s are glowing from the heater (orange) and from the plate voltage (blue). So, try the experiment with the Mesa tubes to see if you can tell that the high-voltage is on. If you flip the Standby switch, and don't see the blue glow, then you may have a bad recording/mute switch. Also, if you have another amp, run it with your combo's speaker, just to take that out of the equation.

 

[Lt_Core]

Here's the deal: blown C90 speaker!

****, we don't play that loud. He said there was some defect in the speaker. Who knows...

He has some in-stock speakers:

Jensen NEO 100 (more warm, tighter bass than the C90)
G12 75 ( similar to the C90 black shadow)
G12 70 (used speaker, no warranty, no thanks)

I've heard good things about the NEO 100's. Any thoughts? In the end, he said it will cost just over $100. Not bad I guess.

 

[disassembled]

Why settle for what he has in stock? 3 speakers is a horrible selection. Go to avatarspeakers.com and ask Dave for some recommendations or even Ted at tedweber.com This is an oppurtunity for you to upgrade not just settle for what the guy has. Most decent new speakers will be around 100-110 dollar range. Just my nickels worth.

 

[disassembled]

Oh just FYI an easy way to test out a speaker is to take a 9Volt battery and place it on the terminals of the speaker. If the cone jumps the speaker is usually good. I am sorry I am just mentioning it now but I just remembered it.

 

[Lt_Core]

Why settle for what he has in stock? 3 speakers is a horrible selection. Go to avatarspeakers.com and ask Dave for some recommendations or even Ted at tedweber.com This is an oppurtunity for you to upgrade not just settle for what the guy has. Most decent new speakers will be around 100-110 dollar range. Just my nickels worth.

I totally agree with you, however, we have gigs this Friday (tomorrow) and Saturday night. I will have a chance to evaluate other speakers after the weekend. From what I've read, the Jensen NEO 100 is pretty good speaker so I'm taking a chance. Never did care for the C90 Black Shadow all that much anyway. I'll keep you posted on how the gigs turned out.