I have an early model mark 3, recently (last night on the gig) I had an issue with the volume fading and then returning in all modes, eventually I had no volume. I switched pre amp tubes 1 and 2 but that did not help. After the amp was off for a few minutes it worked when turned back on but then faded again. Any input or advice would be greatly appreciated. Paul
mark 3 volume
- Thread starter ptkrayer
- Start date
Help Support The Boogie Board:
Check the speaker connection.
Check the effects loop jacks. There's an extra set of connections which connect the send and return jacks to each other when the loop is not being used.
With age and dis-use, the jacks lose connection and need to be bent back or cleaned.
Don't use WD-40. Use De-Oxit.
Sometimes just working a plug in and out a few times works.
Of the jack.
Check the effects loop jacks. There's an extra set of connections which connect the send and return jacks to each other when the loop is not being used.
With age and dis-use, the jacks lose connection and need to be bent back or cleaned.
Don't use WD-40. Use De-Oxit.
Sometimes just working a plug in and out a few times works.
Of the jack.
Thank you, I'll give it a try. Some additional information is: I had this problem about 6 months ago and had it gone over thoroughly by a certified mesa tech. He consulted mesa and they thought it was a tube issue, I've been through many tubes without success. Here are some of the possibilities the tech voiced:
"it's possibly something going down with the filament supply or the B+ power supply. The tracks for the filament supply are on the underside of the cirucuit board which makes things a bit more extensive (pretty much have to gut the amp and pull the board out to inspect/repair the filament tracks). Or a faulty stand by switch".
Any comments welcome.
"it's possibly something going down with the filament supply or the B+ power supply. The tracks for the filament supply are on the underside of the cirucuit board which makes things a bit more extensive (pretty much have to gut the amp and pull the board out to inspect/repair the filament tracks). Or a faulty stand by switch".
Any comments welcome.
SonicProvocateur
Well-known member
I know this may sound silly, but if you are running pedals check your batteries/power supply. I thought my Mark III had died once, and it was just a dumb dead battery in a delay pedal.
Always start with the easy stuff first; cables/batteries, etc.
Always start with the easy stuff first; cables/batteries, etc.
dodger916
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Definitely take the faulty switch! :wink: Sorry, I couldn't resist. Just trying to inject a little humor. Problems like this really suck. You have my moral support.ptkrayer said:
McBarry
Well-known member
Any more info yet Paul on symptoms?
As the others noted, there's a HUGE scope of causes, U really need more info on symptoms when it occurs eg: are tubes still glowing healthily, any unusual sounds with the fade-out, any smells etc etc.
If yr comfortable/skilled at working inside with amp on, the chopstick method trying to elicit fault(s) from loose components or solders joints may yield results.BUT, not to be tried unless U have experience - there's lethal stuff in there that needs a healthy respect and distance.
But also, with amp off, visually inside U may be lucky enough to see burnt bits/areas - something/anything that points to a fault..
Good luck, Dave
As the others noted, there's a HUGE scope of causes, U really need more info on symptoms when it occurs eg: are tubes still glowing healthily, any unusual sounds with the fade-out, any smells etc etc.
If yr comfortable/skilled at working inside with amp on, the chopstick method trying to elicit fault(s) from loose components or solders joints may yield results.BUT, not to be tried unless U have experience - there's lethal stuff in there that needs a healthy respect and distance.
But also, with amp off, visually inside U may be lucky enough to see burnt bits/areas - something/anything that points to a fault..
Good luck, Dave
More info, got home switched in some different power tubes and pre amp tubes...sounded great for a night...next night the volume issues continued... cycling from normal volume to much lower volume and back over a matter of minutes....tubes look fine, no smells...when the volume is
cycling low I can put the master to 6-7 and still not have enough volume to gig and of course when the volume comes back it is quite loud (understatement). I have gigs this weekend, sure to hate to play without it. paul
cycling low I can put the master to 6-7 and still not have enough volume to gig and of course when the volume comes back it is quite loud (understatement). I have gigs this weekend, sure to hate to play without it. paul
McBarry
Well-known member
Still difficult to know if it's power supply or signal.. or both
suggest:
clean/replace the FX jacks. If cleaning, pull them out,remove the metal tabs from the jack chassis to clean thoroughly without forcing things between the contacts, then reinstall tabs and reinstall jacks.
run signal from fx jack to another amp/desk - does the vol drop here when your amp vol drops.
Equally, inject a signal to the return - when vol drops, does the injected signal get attenuated too?
Both these can help point to pre or power amp.
If yr capable working inside, I'd be hunting voltages first, and signal chasising, though the working tech guys here might have some more pertinent tips/ideas.
Also worth a look inside simple to look for burnt/discoloured/abnormal items - never know your luck..
Let us know how U go - solved threads really help everyone..and make good reading.. LOL
suggest:
clean/replace the FX jacks. If cleaning, pull them out,remove the metal tabs from the jack chassis to clean thoroughly without forcing things between the contacts, then reinstall tabs and reinstall jacks.
run signal from fx jack to another amp/desk - does the vol drop here when your amp vol drops.
Equally, inject a signal to the return - when vol drops, does the injected signal get attenuated too?
Both these can help point to pre or power amp.
If yr capable working inside, I'd be hunting voltages first, and signal chasising, though the working tech guys here might have some more pertinent tips/ideas.
Also worth a look inside simple to look for burnt/discoloured/abnormal items - never know your luck..
Let us know how U go - solved threads really help everyone..and make good reading.. LOL
BMcNibbnles
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I know the answer to this.
The Mark III is SO loud and you were jamming on it one day so much that it made you go deaf. The amp is fine. It's your HEARING that's cutting in and out.
Problem solved.
LOL
The Mark III is SO loud and you were jamming on it one day so much that it made you go deaf. The amp is fine. It's your HEARING that's cutting in and out.
Problem solved.
LOL
Have you checked the fuse? I had a very similar issue with my Mark IV it was brand new came in from Mesa didn't spend a day in the guitar store. I brought home and within days the volume went all screwy all the time I brought it back the guys at the guitar store put in a new fuse and worked perfect ever since.
Try it if you haven't already. Take the fuse out from the back and bring it into a radio shack and get them to get you one the exact same, will cost you a buck or two and maybe it'll do the trick?
Let us know, good luck!
Try it if you haven't already. Take the fuse out from the back and bring it into a radio shack and get them to get you one the exact same, will cost you a buck or two and maybe it'll do the trick?
Let us know, good luck!
Okay thanks for sharing. I had the exact same problem with my Mark IV and it was the fuse. Good luck, I'm sure it's in good hands now with tech you sent it, do share what the cause is when you find out so we can all learn
So here we go...this is the description of the repair from John Littlewood certified life saver...
Paul, When I powered up the amp on the bench it had no sound from the get go. I moved the pre tubes a little and then the volume rose up. But after only a few seconds it slowly faded back out to none. s I checked voltages on V2 and sure enought the filament AC voltage was fluctuating from around 5.4 volts down to less than 3. There would normally be over 6volts AC here. I turned off my bench light to look at the filaments and clearly when I held V2 against the socket it would light up and return the sound. This told me there was a problem in the traces and or solder joints on the tube sockets on the underside of the PC board where the filament traces are located. To remove the PC board requiers removing all the control knobs and nuts from the front pots as well as disconecting several of the wires which connect it to the output, reverb, power supply and filaments. I could see from the top side that the filament wires from the transformer were sloppily attached from the previous xformer replacement but when I finally got it all loose and could turn it over it was evident that the traces and thru holes where the filament connects to the heavy silver wires (for the output tubes) had been burned off and the solder was blackened from heavy current. (This happens when the resistence rises and the voltage goes down) I attached some 18ga. copper wired further up on the traces and routed them out of the old holes to reattach the filament connections. I then got out the magnefying glass and inspected the entire filament circuit as well and just went ahead and reflowed all the tube socket pins especially the filament connections. While there I replaced the DC filament filter Cap which can only be unsoldered from under side of the board as it is a radial lead cap. When I was satisfied that could find no more suspect solder joints nor see any breaks in the filament traces or other wise I reassembled the amp. This takes about an hour. then fired her up and woohoo!!! I played it with my Ibanez for about 30 minutes with no problems. Then I left it powered on the rest of the day and played it a few minutes every so often with no problems. Next morning I fired it up and played for almost an hour. This was the fun part cause that great touch sensitivity was back and those tung sols and winged C's were really pumping out great tone. Satisfied that I had solved the issue I contacted you and boxed it back up.
So there the guys on the Boogie Board should enjoy this one. I'm known as "Restless Rocks" and I several hundred posts. Mostly helping guys solved problems with there boogies all around the world.
Thank you John for everything, sincerely Paul
Paul, When I powered up the amp on the bench it had no sound from the get go. I moved the pre tubes a little and then the volume rose up. But after only a few seconds it slowly faded back out to none. s I checked voltages on V2 and sure enought the filament AC voltage was fluctuating from around 5.4 volts down to less than 3. There would normally be over 6volts AC here. I turned off my bench light to look at the filaments and clearly when I held V2 against the socket it would light up and return the sound. This told me there was a problem in the traces and or solder joints on the tube sockets on the underside of the PC board where the filament traces are located. To remove the PC board requiers removing all the control knobs and nuts from the front pots as well as disconecting several of the wires which connect it to the output, reverb, power supply and filaments. I could see from the top side that the filament wires from the transformer were sloppily attached from the previous xformer replacement but when I finally got it all loose and could turn it over it was evident that the traces and thru holes where the filament connects to the heavy silver wires (for the output tubes) had been burned off and the solder was blackened from heavy current. (This happens when the resistence rises and the voltage goes down) I attached some 18ga. copper wired further up on the traces and routed them out of the old holes to reattach the filament connections. I then got out the magnefying glass and inspected the entire filament circuit as well and just went ahead and reflowed all the tube socket pins especially the filament connections. While there I replaced the DC filament filter Cap which can only be unsoldered from under side of the board as it is a radial lead cap. When I was satisfied that could find no more suspect solder joints nor see any breaks in the filament traces or other wise I reassembled the amp. This takes about an hour. then fired her up and woohoo!!! I played it with my Ibanez for about 30 minutes with no problems. Then I left it powered on the rest of the day and played it a few minutes every so often with no problems. Next morning I fired it up and played for almost an hour. This was the fun part cause that great touch sensitivity was back and those tung sols and winged C's were really pumping out great tone. Satisfied that I had solved the issue I contacted you and boxed it back up.
So there the guys on the Boogie Board should enjoy this one. I'm known as "Restless Rocks" and I several hundred posts. Mostly helping guys solved problems with there boogies all around the world.
Thank you John for everything, sincerely Paul
Oh by the way the amp is 1985 Mark 3 black dot...though during the mid 90's I was going through many, many power tubes so I called mesa and they recommended that I have a smaller transformer installed....having no technical skills or understanding of the ramifications, I agreed and they sent me a rectifier transformer at cost...the amp still sounded very good but never the same...I kept the old transformer for years but finally let it go (a mistake of ignorance at the time) Any way that's the story, I just wish I had been better informed, especially from mesa. p
McBarry
Well-known member
Hey John, was this the 3300uf cap U mentioned in another thread in reply to my Q ?
Agreed, the preamp board is a pain to get out..
Dave
Agreed, the preamp board is a pain to get out..
Dave
