Express 5:50 Plus Warranty Repair

5:25 and 5:50's

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Granddrink
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Express 5:50 Plus Warranty Repair

Post by Granddrink » Mon Jul 27, 2015 12:49 pm

I had a failure of my one year old Mesa Express 5:50 Plus head and had it repaired under warranty. It was a difficult problem to diagnose and it began to fail at a gig by distorting and losing power on the clean channel (Channel 1). I tried to troubleshoot it by replacing the power tubes and eventually all of the preamp tubes with no improvement. At some point the reverb quit too. After bringing it to a local Mesa authorized repair shop, the final story from the repair tech was that the reverb failed due to a switching transistor and the distortion was caused by a bad capacitor.
Mark V
Express 5:50 Plus

GuyB
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Re: Express 5:50 Plus Warranty Repair

Post by GuyB » Mon Jul 27, 2015 2:33 pm

Interesting for me to know that : I just had the same problem with my 5:25 Plus (two years old). On channel Clean, distortion and loss of power. Other channels didn't seem to loose power but they sounded a bit distorted too (ugly distortion). It's now at my Mesa authorized repair shop after I changed all the tubes to no avail. I'll keep your post in mind if they don't find anything.

Newysurfer
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Re: Express 5:50 Plus Warranty Repair

Post by Newysurfer » Mon Aug 03, 2015 3:48 am

Granddrink wrote:I had a failure of my one year old Mesa Express 5:50 Plus head and had it repaired under warranty. It was a difficult problem to diagnose and it began to fail at a gig by distorting and losing power on the clean channel (Channel 1). I tried to troubleshoot it by replacing the power tubes and eventually all of the preamp tubes with no improvement. At some point the reverb quit too. After bringing it to a local Mesa authorized repair shop, the final story from the repair tech was that the reverb failed due to a switching transistor and the distortion was caused by a bad capacitor.
ok thanks for the info :)
Gretsch Jet Firebird, Gretsch G5422, Gibson SG Deluxe, Strat Plus - Mesa 5:50, Mesa Mark V 25, analog pedal boards
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nevermind
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Re: Express 5:50 Plus Warranty Repair

Post by nevermind » Sun Apr 02, 2017 7:15 am

Granddrink wrote:I had a failure of my one year old Mesa Express 5:50 Plus head and had it repaired under warranty. It was a difficult problem to diagnose and it began to fail at a gig by distorting and losing power on the clean channel (Channel 1). I tried to troubleshoot it by replacing the power tubes and eventually all of the preamp tubes with no improvement. At some point the reverb quit too. After bringing it to a local Mesa authorized repair shop, the final story from the repair tech was that the reverb failed due to a switching transistor and the distortion was caused by a bad capacitor.
Not sure if the OP is still around but I'm curious, how many hours on the amp when it began to fail? Doesn't most solid state stuff fail very soon after putting power to it or not at all? (unless of course an external event triggers it.)

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