Amp turning off and on again quickly

Discussion for the new Mark V

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bandit2013
Triple Recto
Posts: 3142
Joined: Fri Feb 22, 2013 7:31 am
Location: North Carolina

Re: Amp turning off and on again quickly

Post by bandit2013 » Sat Feb 03, 2018 6:54 pm

I see. I hope you get a resolve on your issue.

Hathor
Bottle Rocket
Posts: 13
Joined: Wed Jan 31, 2018 3:17 pm

Re: Amp turning off and on again quickly

Post by Hathor » Sat Feb 03, 2018 9:27 pm

bandit2013 wrote:I see. I hope you get a resolve on your issue.
Thank you!

With the help provided by all you friendly and knowledgeable people on this board, I feel like I am ready to send the amp in for service.

In a second reply from MESA the tech writes:
HI [name removed],

Yes, I did receive your message. One of our workers dislocated his shoulder in hockey game (how delightfully Finnish by the way:-D) . Now I have to do most of his work too for awhile so I´m a bit overbooked. Sorry for the delay.

Power cable is checked. The only possible thing I see is power tube badly seated(not fully in) in its socket. But symptoms dont really point there though it´d be easy to for you to check. Not much more you can do for yourself really.

Of course there can be outside issues like badly regulated power. This happens sometimes in training rooms as the current available fluctuates and affects the amps inner voltages which confuses the amps relays. Or short circuits elsewhere in the signal chain(most usually in speaker cabs).

Denmark has been difficult market for us as no dealer is willing to give effort to Boogie. This means your closest Official Service Station is in Malmö, just over the Bridge. Great store, knows Boogie and they have Service Station inside with exclusive access to Mesa/Boogie Tech Support. You don´t have to ship your amp to USA. I´ll include Malmö contact info here:
As the diodes as mentioned in a previous post by another user affects the relays I really think I have come closer to a solution and a fix.

I will update this thread with information about the outcome of all this, and try to get the tech to give an explanation of what caused this issue, for future reference in case that some MESA owner in the future will face the same problem and have the same troubles I had getting a grasp on how to understand and describe the problem to a service center.

Also, this tech from Finland, whoever he may be is a very friendly and professional person and that is simply a great feeling when you are frustrated and troubled by the thought of just having to make do with a malfunctioning amp.

I thank you all.

royslead
Mark II
Posts: 113
Joined: Sat May 31, 2014 11:00 pm

Re: Amp turning off and on again quickly

Post by royslead » Fri May 18, 2018 12:25 pm

So, are there any updates to report on this issue? I ask, because I just noticed the same behavior with my Mark V (90) head. EXACT symptom.

notyalcer
Mark I
Posts: 22
Joined: Fri Apr 13, 2007 12:31 pm

Re: Amp turning off and on again quickly

Post by notyalcer » Sat May 19, 2018 9:32 am

I have very similar symptoms with my amp. Very random but probably once a week the amp will shut down and back on. I hear the fan shut off, the relays click, and then everything starts up again, all within a second or less. Occasionally it will do it again within a few seconds. It seems once the amp is warmed up for a few minutes it doesn’t happen, it seems always within a minute of turning it on from a cold start.

One detail that I did not see in the OPs original description of the problem is this: when it happens to my MK V, the foot switch immediately goes into “power up” mode, whereby all three channel LEDs are illuminated at once. The amp reverts to the clean channel. Does this also happen when your amp momentarily shuts down and back on again?

Thanks for any updates on your situation and best of luck!

Hathor
Bottle Rocket
Posts: 13
Joined: Wed Jan 31, 2018 3:17 pm

Re: Amp turning off and on again quickly

Post by Hathor » Sat May 19, 2018 1:38 pm

royslead wrote:So, are there any updates to report on this issue? I ask, because I just noticed the same behavior with my Mark V (90) head. EXACT symptom.
notyalcer wrote:I have very similar symptoms with my amp. Very random but probably once a week the amp will shut down and back on. I hear the fan shut off, the relays click, and then everything starts up again, all within a second or less. Occasionally it will do it again within a few seconds. It seems once the amp is warmed up for a few minutes it doesn’t happen, it seems always within a minute of turning it on from a cold start.

One detail that I did not see in the OPs original description of the problem is this: when it happens to my MK V, the foot switch immediately goes into “power up” mode, whereby all three channel LEDs are illuminated at once. The amp reverts to the clean channel. Does this also happen when your amp momentarily shuts down and back on again?

Thanks for any updates on your situation and best of luck!
My amp has been in a repair shop for nearly 3(!) months - since the beginning of March until now. I haven't got it back yet. The tech was able to actually see the issue with his own eyes which by itself was almost a miracle.


They soldered everything off and back on, and they believe that the issue is located in the diodes in the 12V circuit and have replaced that but they also say that they have no way of testing and reproducing the error, so it is anyone's guess if it is actually fixed.

It is very, very frustrating.

With regards to the foot switch, I simply haven't noticed if it behaves odd when it happens - the time is too short and all my focus has been on the amp itself.

All I can say about the foot switch is that when the amp comes back on, the foot switch will turn on on the same channel as it was before shut down.

I hope you guys get it fixed but be prepared for a lengthy and frustrating experience.


Best regards from Denmark.

jaslan
Mark II
Posts: 63
Joined: Fri May 06, 2016 10:25 am

Re: Amp turning off and on again quickly

Post by jaslan » Sat May 19, 2018 3:53 pm

notyalcer wrote:I have very similar symptoms with my amp. Very random but probably once a week the amp will shut down and back on. I hear the fan shut off, the relays click, and then everything starts up again, all within a second or less. Occasionally it will do it again within a few seconds. It seems once the amp is warmed up for a few minutes it doesn’t happen, it seems always within a minute of turning it on from a cold start.

One detail that I did not see in the OPs original description of the problem is this: when it happens to my MK V, the foot switch immediately goes into “power up” mode, whereby all three channel LEDs are illuminated at once. The amp reverts to the clean channel. Does this also happen when your amp momentarily shuts down and back on again?

Thanks for any updates on your situation and best of luck!

This sounds exactly like the failing diodes I had. Eventually, the amp just died and wouldn’t come back on. It was under warranty so they sent me to a tech who replaced them in about 2 hours (actually let me stay and watch/assist) and it has been good every since. I recommend you just go ahead and talk to Mesa service and schedule the diode replacement.

royslead
Mark II
Posts: 113
Joined: Sat May 31, 2014 11:00 pm

Re: Amp turning off and on again quickly

Post by royslead » Sun May 20, 2018 1:34 pm

I have not noticed the foot switch symptoms, just the clicking, lights at the amp cycling rapidly; and usually just once, then it's ok.

notyalcer
Mark I
Posts: 22
Joined: Fri Apr 13, 2007 12:31 pm

Re: Amp turning off and on again quickly

Post by notyalcer » Fri May 25, 2018 8:52 am

jaslan wrote:
notyalcer wrote:I have very similar symptoms with my amp. Very random but probably once a week the amp will shut down and back on. I hear the fan shut off, the relays click, and then everything starts up again, all within a second or less. Occasionally it will do it again within a few seconds. It seems once the amp is warmed up for a few minutes it doesn’t happen, it seems always within a minute of turning it on from a cold start.

One detail that I did not see in the OPs original description of the problem is this: when it happens to my MK V, the foot switch immediately goes into “power up” mode, whereby all three channel LEDs are illuminated at once. The amp reverts to the clean channel. Does this also happen when your amp momentarily shuts down and back on again?

Thanks for any updates on your situation and best of luck!

This sounds exactly like the failing diodes I had. Eventually, the amp just died and wouldn’t come back on. It was under warranty so they sent me to a tech who replaced them in about 2 hours (actually let me stay and watch/assist) and it has been good every since. I recommend you just go ahead and talk to Mesa service and schedule the diode replacement.
That is helpful information! Thank you. I have only owned my Mark V for a few months, got it used with 2 years left on the tanferable warranty. I have not playing this amp live yet, not gigging that much but have some gigs coming up in late summer/fall. If the amp did this routine during a performance, it would reset to the clean channel which could be disconcerting while playing, but not a total disaster.

Probably need to get this fixed while under warranty. You may have already mentioned, but which diodes were failing? Thanks!

jaslan
Mark II
Posts: 63
Joined: Fri May 06, 2016 10:25 am

Re: Amp turning off and on again quickly

Post by jaslan » Sat May 26, 2018 7:11 am

notyalcer wrote: ...which diodes were failing?
All I know is they were in the power supply section... I think...

Rockstarlineman
Bottle Rocket
Posts: 1
Joined: Sun Oct 06, 2019 6:47 pm

Re: Amp turning off and on again quickly

Post by Rockstarlineman » Sun Oct 06, 2019 6:53 pm

from bandit2013
It could also be associated with the 12V voltage regulator which is connected to the chassis for thermal dissipation. this circuit is formed from a separate power tap on the PT and supplies power to three preamp tube heaters, cooling fan and 5v voltage for the channel controller. I believe that the relays also run on the 12v supply as well as the diodes to indicate function. If this circuit is dropping out it will be basically shutting down the amp even though there is power to the power tubes and preamp tubes. There are three preamp tubes that use the 12Vdc heater circuit : V1, V2 and V5. I If there is a fault in the heater of either of these tubes (shorting out intermittently) you could replace all three with new tubes and see if the problem is persistent. The power light is also an LED and most likely is supplied by this circuit.

I looked up the LM2940 (12V voltage regulator) data sheet. In its description, it has an overvoltage protection ciruit that will momentarily shut down the regulator in the event the intput voltage is exceeded. This could be related to a gound loop transient voltage spike or from the power transformer or associated circuits.

This I reposted is exactly what I think is wrong with mine as well. so now Im wondering how to fix it? anyone have a video on how to fix it? mine is out of warranty. the reason why I think it is this and not diodes is because the description fits perfectly . the fan quit, no led on the power, the tubes are all lit up so I believe its a low voltage issue. Please help...

jdgebha
Mark I
Posts: 32
Joined: Mon Dec 09, 2013 1:55 pm

Re: Amp turning off and on again quickly

Post by jdgebha » Mon Oct 07, 2019 4:39 pm

Had the exact same symptoms. Took to an authorized mesa tech and he a diode replacement and a power supply upgrade recommended by mesa. No probs a year amd a half later.

Giz-Tone
Mark I
Posts: 37
Joined: Fri Jan 24, 2014 2:31 pm

Re: Amp turning off and on again quickly

Post by Giz-Tone » Wed Oct 09, 2019 3:09 am

The same thing happened to my amp. The diodes in the LV power supply needed to be replaced. It seems like a common fault with the Mark V

richprice79
Mark I
Posts: 32
Joined: Mon Apr 17, 2017 5:55 pm

Re: Amp turning off and on again quickly

Post by richprice79 » Thu Nov 07, 2019 10:12 am

Well my 2017 Mark V 90 is having the same issue. I don't have any local Mesa repair shops so I called and they recommended I mail it to California from St. Augustine Florida. I asked if they could send me a factory box with the form fitting packing material for a cost and they will do that for around $40.00. It sucks but seeing others have the same issue makes me feel less unlucky. I can't imagine what the shipping to Mesa bill will be as I will want it there fast to avoid damage.

Giz-Tone
Mark I
Posts: 37
Joined: Fri Jan 24, 2014 2:31 pm

Re: Amp turning off and on again quickly

Post by Giz-Tone » Fri Nov 08, 2019 2:35 pm

richprice79 wrote:
Thu Nov 07, 2019 10:12 am
Well my 2017 Mark V 90 is having the same issue. I don't have any local Mesa repair shops so I called and they recommended I mail it to California from St. Augustine Florida. I asked if they could send me a factory box with the form fitting packing material for a cost and they will do that for around $40.00. It sucks but seeing others have the same issue makes me feel less unlucky. I can't imagine what the shipping to Mesa bill will be as I will want it there fast to avoid damage.
I was going to send my amp back to my nearest mesa distributor. There's none in my country, I'd have to send it abroad (not the USA) to be repaired.

It turned out that the Mesa distributor would lease the repair work out to a third party. Some local dude near the distributor in other words.

My point is that if you can find a good local tech, go with him. He can order the resistor's and tech info from Mesa. It will be a lot cheaper.

It's a quick fix, and a good tech should have the necessary parts already.

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