Amp turning off and on again quickly

[jaslan]

Thanks. I will try that. It is certainly easy enough to give it a shot.

 

[guijs]

My tech replaced 5 diodes and a regulator. He said it was odd that the regulator did not had a thermal paste between it and the chassis. He also resoldered the joints on the power switch. I played for 2 hours yesterday and didn't had any problems. BTW, we also tested the footswitch and did not found any problems.

Apparently my problem was solved. But important to say that the amp did not fail a single time (without the FS, it was with me) when being tested by my tech, but I asked for him to replace the components anyway. We can't know for sure what was the problem.

 

[SCSurfAddict]

I had this “power blink” problem as well.

About once per week the amp would power off/on in a blink and on reset to channel 1. Everything else was fine.

My amp was manufactured just after Mesa fixed the diode issue (2015/16). I live in Northern California so I took my Mark V to Petaluma and had Mesa check it out. Diodes were ok. Evidently I had an issue with the power switch solder joints. They resoldered everything and im back in business. If the problem resurfaces I’ll post something. Hope this helps someone

Update to the above:

After a week back from the factory repair shop, the blink/reboot began again. Fortunately I kept pushing it until it failed altogether. I took it back to the Petaluma factory and they found a bad diode in the low voltage side of the amp (12v). They replaced all 4 of these diodes as a precaution. It works great now.

Btw, after the blink became a hard failure, the front panel was dark, the amp silent but the tubes were lit.

I hope this helps someone.

 

[G Mac]

Well, it's been awhile! My amp is on its way back to me from Cali! It's been with them for almost a month! I talked to Rich in Repair...he said that they replaced the footswitch I.C.. They were unable to recreate the problem sooo...we'll see what transpires. Hopefully, it'll be fine and there won't be any further issues. I'm excited to get it back; I've missed that tone! As always, I hope you're all well and I'll keep you posted! Wish me luck!

 

[G Mac]

Hey, All! Just here for yet another update. Got my beauty back and almost immediately experienced the same problem except maybe a bit more pronounced than before! So, the problem is not the footswitch I.C.. Tomorrow, I'm going take her to the music store where I teach and see if I can replicate the issue. One thing though, when the footswitch is not connected the problem doesn't occur. This leads me to believe that dirty power is not the problem. What say you? Jaslan, did your amp stop doing the thing when you unplugged the F.S.? And SCSurfAddict, is your amp still working properly?I would like to know so that I can narrow down the possibilities somewhat. I'll keep posting updates until I get this business solved...hopefully this thread will help others with the same or similar issues. Wishing you all well! The saga continues... :roll:

 

[jaslan]

Oh, I forgot about trying that! I built a Mojotone Princeton Reverb clone a few months ago and have been having so much fun playing that that I haven't even turned on my MV in probably a month. But last night, I powered it up and while it was in STBY, it clicked quickly once, then about 10 seconds later it completely went quiet and blank and stayed that way for about 10-15 seconds. I stared at it very intensely during that time and it decided to come back to life! I then played the amp for about an hour with no problems. I have noticed, in the past, the problem tends to happen in the first 15 minutes or so after powering up, like something needs to warm up. I bought the Tazmanian Blackwood version with the matching 2 x 12 vertical recto so it will never leave my house anyway, so I have decided to just wait until it dies completely and then I will take it for repair. I don't want to bother with the "could not duplicate" maintenance action. But the fact that it died completely (with no lights on the front panel at all and the fan went quiet) makes me think it is the power supply diodes again. I got mine in 2014 so it is out of warranty by now but if and when I do send it in maybe Mesa would give some relief since it has really been an ongoing issue. I still love the amp though.

 

[G Mac]

Thanks for your reply jaslan! Glad to hear about your new Mojotone! I have a friend who just finished a Deluxe clone and he loves it! Anyway, took my girl to the store today and...not a problem! I played for about two hours and it performed perfectly! All the guys at the store agreed that it was the best sounding amp they ever heard. Most of them had never seen a Boogie in person. So, I guess I'll keep on checking and rechecking the variables. At this point it looks like I'll have to have an electrician come and check the current(s) in the house. I guess I'll just run it w/o the F.S. at home...I've gigged the amp three times with no problems. Maybe I'll get "lucky" like SCSurfAddict and get a hard failure. At least then the diagnosis should be easier. As always, I'll keep you abreast of the situation as I progress. Peace!

 

[G Mac]

Okay, I'm back with what I hope will be my final update on this thread! So, the house current seems to be good. I talked to Rich at Mesa repair and he suggested that I take it to their authorized guy that I've been seeing in order to have the four diodes replaced. Rich said that the diode issue is not confined to a particular set of serial numbers and is still occurring on occaision. So. the diodes have been replaced. I picked up the amp yesterday and brought it home and played for a couple hours with the footswitch and...No Problem! Usually the blink would occur within the first 15 to 20 minutes of powering up. I played all three channels with and without the EQ engaged (the problem seemed to happen most often on channel 3). I'm hoping that this spells the end of my trouble with this amp! In summary, it seems that the problem was with the four pernicious diodes that have been an issue for quite some time now. I hope that my experience will help someone else with this problem. Thank you all for your helpful advice! If you don't hear from me again, you'll know that all is well. Peace!

 

[jaslan]

Rich said that the diode issue is not confined to a particular set of serial numbers and is still occurring on occaision. .....it seems that the problem was with the four pernicious diodes that have been an issue for quite some time now.

I am glad you posted this. I got my MKV in 2014 and about a year or two later, the diodes were replaced. The "word on the street" at the time was that it was a bad batch of diodes. I don't know if that was coming from Mesa (maybe they thought that at the time) or if it was coming from guys on this forum. But, after my repair and the symptoms have been mildly back for at least a year now, I suspected that it wasn't just a bad batch of diodes but perhaps something about the design makes it slightly more prone to this type of failure. I don't want to say a design "flaw" or anything wrong with the design. Of course, all parts can fail and there will always be some type of failure that ends up being the most common. Maybe, for the MKV, this is the most common failure. Anyway, mine still doesn't "click" very often and it still seems to only happen in the first 15 minutes after powering up so it's not a huge issue for me but I have kind of accepted the notion that it may eventually go completely dead (again, like the first time) and I will have to get the diodes replaced again.

Anyway, it is actually kind of a relief to see that Rich from Mesa said it was not necessarily just a bad batch of diodes...

 

[SCSurfAddict]

G Mac

Sorry for the delay in posting. It looks like you are back up and running. I love my Mark V when its working . After 2 months mine is working perfectly. The low voltage rectifier fixed it. I’ve
Gone from Love to Hate back to Love. There aren’t many tones I can’t squeeze out of it.