Mark V briefly loses power, then comes right back on?

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It is good to hear you may have a resolve on your issue. Did you send the amp with the power tubes installed or did you remove them when you shipped it for repair?

I have had other issues with my Mark V but nothing like what you have experienced. I did have a similar problem but was related to rectifier tube and power tubes and eventually a screen resistor. I have not had any issues since the repair.
 
bandit2013 said:
It is good to hear you may have a resolve on your issue. Did you send the amp with the power tubes installed or did you remove them when you shipped it for repair?

I had the option of sending the tubes to have them tested as well, or just the chassis without the tubes. I did send my tubes in and they all tested fine...... It was my power supply with the additional possibility of something in the footswitch jack causing issues. But more than likely, the power supply.

I played a 4 hour show last night, plus sound check and a quick practice pre-show... A total of almost 5 1/2 hours and it did not give me any problems.
 
I had the same problem last year but it only happened once, and right after the power came back on the rectifier tube started smoking and then died. I took it to an authorized repair guy and he checked the amp out completely and replaced the rectifier tube. The amp had no problems that he could find and since replacing the rectifier tube i have had no further problems.
So if you haven't already, try replacing the rectifier tube.
Good luck.
 
kreatorkills said:
I had the same problem last year but it only happened once, and right after the power came back on the rectifier tube started smoking and then died. I took it to an authorized repair guy and he checked the amp out completely and replaced the rectifier tube. The amp had no problems that he could find and since replacing the rectifier tube i have had no further problems.
So if you haven't already, try replacing the rectifier tube.
Good luck.

I already sent it in and got it back right after Christmas.... They found some bad components in the power transformer and some issues with the footswitch jack and re-tensioned the input.

I did replace the rectifier tube prior to sending it in, no fix.
 
I started experiencing this a few months ago. My amp is about 6 months old. It would happen once or maybe twice a day playing 2-4 hours per day or, sometimes not at all for several days. At first, it was very quick and i wasnt even sure what was happening. Then, once it went off for about 2 seconds and when it came back, the channel had reset to channel 1 and all 3 channel footswitch lights were on (like i had just turned on the power from a cold start up). This is when i started to suspect power problems. I talked to support and they said i may be experiencing low voltage in my house. So i tried to keep an eye on that (i have a rack mount power strip with a voltage readout but the amp was plugged directly into the wall per supports recommendation). It continued to cut out occasionally and then, the other day, it cut out and reset to channel 1. There were no lights on the front panel of the head or footswitch and the sound faded out over the 15 seconds or so. Now the amp wont come on at all. I can see when the power switch is on, that the power tube filaments are getting power and glowing orange but no sound or lights anywhere on the amp or footswitch.
I talked to support again and they seemed fairly certain of low voltage condition at my location and he did mention that they have been seeing this problem. He said there is a "tech order" update that replaces some components in the power supply that should fix the problem by making it less sensitive to momentary low voltage conditions (or at least that was my understanding).
I contacted the nearest repair shop and he ordered the components and once he gets them i will take the head in and he said it should only take an hour or two. I am hoping that fixes everything and will post the results here.
I live a a town of about 45,000 people in an area with plenty of new development and our house is less than 20 years old and i have never had any trouble so far in our 8 years of living here with appliances or my old amp, etc. i am hoping the diagnosis is correct and it just needs a more robust power supply. I guess if that doesnt do it i may have to look into a voltage regulator.

Anyway, back to Guitar Rig for, hopefully, only a week or two... :oops:
 
I got my amp fixed. I was fortunate enough to have a qualified repairman within driving distance from my home. He was very accomodating (New Orleans repair location) and allowed me to coordinate bringing in the amp at a time when he was able to work on it immediately. In fact, he let me stay and watch and actually taught me some things about handling the tubes and taking the chassis out in case I ever need to send it somewhere, etc.
Anyway, when we plugged in the amp at his shop, it was still "dead" with no lights on the front panel at all but the tubes were getting power as indicated by the orange glowing "filaments". There are 4 diodes that the support tech had instructed him to replace with new ones that they sent to him. Before removing the old ones he tested them and 2 of them did, in fact, fail the test. After replacing all four diodes and putting the tubes back in, the amp powered up and worked flawlessly. We tested all the channels, etc. I have had the amp back at home for four days now and have put about 6 hours on it and have not had any "cutouts" so far. Mesa support was right on with the diagnosis and the fix.

In total, my amp was only out of commission for six days. The repair tech had the parts in hand the day AFTER in called support. The extra couple of days was actually my waiting for a day I was able to take it in.

Anyway, incredible support from Mesa and the repairman!

I hope this post helps someone. :p
 
jaslan said:
I got my amp fixed. I was fortunate enough to have a qualified repairman within driving distance from my home. He was very accomodating (New Orleans repair location) and allowed me to coordinate bringing in the amp at a time when he was able to work on it immediately. In fact, he let me stay and watch and actually taught me some things about handling the tubes and taking the chassis out in case I ever need to send it somewhere, etc.
Anyway, when we plugged in the amp at his shop, it was still "dead" with no lights on the front panel at all but the tubes were getting power as indicated by the orange glowing "filaments". There are 4 diodes that the support tech had instructed him to replace with new ones that they sent to him. Before removing the old ones he tested them and 2 of them did, in fact, fail the test. After replacing all four diodes and putting the tubes back in, the amp powered up and worked flawlessly. We tested all the channels, etc. I have had the amp back at home for four days now and have put about 6 hours on it and have not had any "cutouts" so far. Mesa support was right on with the diagnosis and the fix.

In total, my amp was only out of commission for six days. The repair tech had the parts in hand the day AFTER in called support. The extra couple of days was actually my waiting for a day I was able to take it in.

Anyway, incredible support from Mesa and the repairman!

I hope this post helps someone. :p

Thanks! My Mark V is having this exact same issue.
 
Rocco Siffredi said:
Thanks! My Mark V is having this exact same issue.

Give Mesa a call...Or have your tech call them. When I spoke to them, they said there were several from a few years ago that they have narrowed it down to the components they got from their supplier (or something like that), but they know which SN's have these parts and replacing them will fix the issue.
 
Here's an update on my situation. After sending my amp to my closest Mesa tech to be repaired, they sent it back to me saying the amp was A okay, nothing wrong. The day it returned it cut out again. Talk about frustration. I reported it to the store I bought it from and they said they would not refund my purchase as Mesa said the amp was fine. So I recorded the fault on video and returned the amp for a second time. This time the store checked it out before sending it on to Mesa. They witnessed the fault and agreed to have it repaired before sending it back to me again.

In the end Mesa replaced the entire amp chassis. Their tech couldn't find what was causing the fault.
 
That is odd, I have not lost power with the tank removed (unplugged). If your amp does not have the stability it would point at a few components on the circuit board or the voltage regulator that is mounted to the chassis. Does it get worse when you select variac power? If you have a bad component in the 5V supply circuit (note that V1, V2 and V5 heaters are supplied by the 12V regulator that feeds into the 5V regulator. Could be a bad heater element on one of the preamp tubes. Just a suggestion.
 
I know this is an old topic but I'm having the exact same problem.

I wish I had a video recording of it happening but the random occurence and quick revert back to normal operation makes it almost impossible to document.

After searching for months this is the first time I find some describing the exact same issue as I'm having. I seriously thought I was the only one in the whole world!

EDIT: Link to my thread about the problem: http://www.forum.grailtone.com/viewtopic.php?f=33&t=74584&p=504950#p504875
 
Giz-Tone said:
Here's an update on my situation. After sending my amp to my closest Mesa tech to be repaired, they sent it back to me saying the amp was A okay, nothing wrong. The day it returned it cut out again. Talk about frustration. I reported it to the store I bought it from and they said they would not refund my purchase as Mesa said the amp was fine. So I recorded the fault on video and returned the amp for a second time. This time the store checked it out before sending it on to Mesa. They witnessed the fault and agreed to have it repaired before sending it back to me again.

In the end Mesa replaced the entire amp chassis. Their tech couldn't find what was causing the fault.

Dude, I'm sorry for being forward but I will PM you in the hopes that you see it and that you still have the video and you will share it with me. I really need to be able to document this error and given I don't play every day and not for several hours at a time it is just impossible for me to record on video.
 
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