Advice on amp blowing fuses Mesa Mark III content

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Mailman1971

Mailman1971

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Ok....get the Mark III red stripe home. Fire it up. Fan kicks on......tubes glowing.
I turned everything to zero then started to dial up.

Got it pretty loud and was dialing in some gain then the thing dies.
Checked the fuse. Blown.

So I grab another fuse 100 slo blo and the same thing happens after about 2 minutes.
I have the 'ground' toggle set in the middle.
Would that be the culprit instead of the A or B setting?

I think I am just gonna send it in to Mesa and get the ++ mod done on it and reworked.
But in the mean time what could be causing this?

:no:
 
Mailman1971":2au5oulp said:
Ok....get the Mark III red stripe home. Fire it up. Fan kicks on......tubes glowing.
I turned everything to zero then started to dial up.

Got it pretty loud and was dialing in some gain then the thing dies.
Checked the fuse. Blown.

So I grab another fuse 100 slo blo and the same thing happens after about 2 minutes.
I have the 'ground' toggle set in the middle.
Would that be the culprit instead of the A or B setting?

I think I am just gonna send it in to Mesa and get the ++ mod done on it and reworked.
But in the mean time what could be causing this?

:no:
Click to expand...
Change the tubes Dano. :thumbsup:
 
Yeah it shipped with Groove tubes.
Going to get a set of Mesa tubes for it.
I know they are designed for that amp.
Well I played it for 5 minutes. Sounded good! :lol: :LOL:
 
Another question. With the Mark Series they are just plug and play even if 6L6 or EL34 as long as they are mesa brand correct?
 
should be , but he whole brand thing is bs, ive put all sorts in my mesas not one prob
 
Mailman1971":exghup2p said:
Another question. With the Mark Series they are just plug and play even if 6L6 or EL34 as long as they are mesa brand correct?
Click to expand...
No Dan. If it is Simulclass you can run 6l6 or 6l6 inner sockets and el34 out sockets. If you run all 6l6 make sure you check the bias in the outers as they can run too hot so you need tubes that will fall into range.
 
Ok.....I got some 6L6's I will pull from my Recto and then 2 of the EL 34's I will run with them.
Grabbing a fuse from another amp and see what happens.
Wish me luck! :lol: :LOL:
 
You could always contact a reputable tube dealer, Tube Depot, Valve Queen, etc and let the know it is for a Boogie and they will select the correct rated power tubes. You you be able run any 12AX7 preamp tubes. I prefer Tungsols.
 
Ok.....just got in. It was all 6L6's and after reading the manual it says simuclass needs to be run in pairs. 6l6 in the inner and EL34 outer. Did just that. Fired it up. :thumbsup:

Gonna try to record something tonite. Man I forgot what a bitch that thing is to dial in. But Its got killer tone. :rock:
 
Well just got in the house. Thing died again. :(
Played it for about an hour so I know its not "broken" :lol: :LOL:
I am going to contact Mesa and ship it off to be serviced and modded.
Not in a hurry. I got few other amps I can play in that time when its gone. ;)
 
Sorry to hear the markIII hunt is still problematic. What's the ++ mod? Only mod I ever felt like it needed was the r2 mod. Never got around to it.
 
Hey Danno I got a shit ton of power tubes laying around here that I'll never use. Pretty sure I got some Mesa branded el34s and 6L6GCs in a box and an ungodly amount of preamp tubes. If you can use any of them I'll have them in the mail tomorrow. Shoot me a text and let me know what's up.
 
Mailman1971":3gqz093o said:
Well just got in the house. Thing died again. :(
Played it for about an hour so I know its not "broken" :lol: :LOL:
I am going to contact Mesa and ship it off to be serviced and modded.
Not in a hurry. I got few other amps I can play in that time when its gone. ;)
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Probably a bad screen grid resistor. They do go in these old Marks. My III had that issue and was popping the fuse. I used a 1 watt fast blo until I isolated it.
 
I would have Mesa put in all fresh tubes and give the entire amp a look over. Make sure you tell them what happened. Might want to ask if there is any other modifications that can be done.
When I talked with Randy last month I asked about any mods that could be done to my IV and Tremoverb. There was none.... But he did ask what I would want to change.... Nothing was my reply.
 
I would probably return it. There are plenty of MK III's for sale without issues.
 
Mailman1971":zr09twzu said:
Ok.....just got in. It was all 6L6's and after reading the manual it says simuclass needs to be run in pairs. 6l6 in the inner and EL34 outer. Did just that. Fired it up. :thumbsup:

Gonna try to record something tonite. Man I forgot what a bitch that thing is to dial in. But Its got killer tone. :rock:
Click to expand...

Verify that the amp is simul-class. There's a few ways to do this if the sticker fell off. Make sure your output transformer is stamped with 562003. This will verify that the amp is simulclass.

You also could tell depending on what power switch was on the faceplate. If it said "full/half power", that used to mean simul-class, and if the switch says "100/60", then it's not simul-class. Personally, I don't trust this method, I'd just verify the OT number.

Edit: and always make sure than you run your EL34s in the outside sockets, unless you have a Coliseum, in which case, you run the EL34s in the center sockets.
 
Crunchtime":1rbaaspo said:
I would probably return it. There are plenty of MK III's for sale without issues.
Click to expand...
This is probably whats going to happen.
While it was running I did an A/B test with my FJA Recto. I could cop the same tone. But better.
Trying to get away from duplicate overlapping tones.
 
Mine did this, it was the screen grid resistor. When I get to my pc I'll post some pics of them. I just got some new ones soldered them in and it's been rockin now for a year or so...
 
Best thing to do is go back and see if they have that blue stripe. Tell them the red is screwed. Tell them you'll give them ... for the blue and take it home :D
 
glip22":271zkhfw said:
Best thing to do is go back and see if they have that blue stripe. Tell them the red is screwed. Tell them you'll give them ... for the blue and take it home :D
Click to expand...
Done.....and DONE!! :D
Blue is in my grubby hands. Ready to ship to Mesa Boogie for the whole Kitchen sink!! :thumbsup:

Oh wait.....different company. :lol: :LOL:
 
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