Ratou
Member
- Joined
- Apr 1, 2014
- Messages
- 19
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Hi all,
Thanks in advance for your help on this as I've been trying to figure this out for a while.
I have a Mk III that has been serviced (new caps) and modded to III+ specs by Mike B a few years ago (2016 I believe, was done by previous owner). While it sounds very good, I have had problems with it blowing fuses consistently after being played for any slightly extended period of time (ie. more than 30 mins). I have tried to troubleshoot the cause to the best of my ability but have not been able to find the issue. I even brought the amp to a very good Mesa/Boogie tech in London (John Kelly) who said it's one the cleanest and most silent Mk IIIs he's seen and wasn't able to replicate the blowing fuse even after leaving the amp on for prolonged duration on his bench. I brought it back home and blew a fuse an hour later...
Symptoms:
-Power transformer gets very hot when amp is played (too hot to touch). Called Mesa on this and the guy I talked to on the phone said it's normal and that I shouldn't worry. Also, the local tech I brought it too said the trannys where fine, he completely checked the amp with a scope and didn't find anything. The reason I mention this is that the fuse holder above the PT (because of PT heat?) gets also very hot (again, can barely touch it) so was thinking maybe the high temps where causing the fuse to be unstable or something?
-Amp blows fuses even with power tubes unplugged. I've left the amp with only the power chord and speaker plugged in (with and without power tubes) and it still blew a fuse after a while.
-It's a 110V amp so I use a step down transformer. I use a very high quality one (rated for 1000+ watts) that has been working very well with other 110V Mesa's (Mark II and Mark IV). They never blew a fuse even after being left on for multiple hours.
Again, thanks a lot for any help on this. I really like this amp and would like to gig with it but unfortunately I've been struggling with this mysterious fuse issue...
Thanks in advance for your help on this as I've been trying to figure this out for a while.
I have a Mk III that has been serviced (new caps) and modded to III+ specs by Mike B a few years ago (2016 I believe, was done by previous owner). While it sounds very good, I have had problems with it blowing fuses consistently after being played for any slightly extended period of time (ie. more than 30 mins). I have tried to troubleshoot the cause to the best of my ability but have not been able to find the issue. I even brought the amp to a very good Mesa/Boogie tech in London (John Kelly) who said it's one the cleanest and most silent Mk IIIs he's seen and wasn't able to replicate the blowing fuse even after leaving the amp on for prolonged duration on his bench. I brought it back home and blew a fuse an hour later...
Symptoms:
-Power transformer gets very hot when amp is played (too hot to touch). Called Mesa on this and the guy I talked to on the phone said it's normal and that I shouldn't worry. Also, the local tech I brought it too said the trannys where fine, he completely checked the amp with a scope and didn't find anything. The reason I mention this is that the fuse holder above the PT (because of PT heat?) gets also very hot (again, can barely touch it) so was thinking maybe the high temps where causing the fuse to be unstable or something?
-Amp blows fuses even with power tubes unplugged. I've left the amp with only the power chord and speaker plugged in (with and without power tubes) and it still blew a fuse after a while.
-It's a 110V amp so I use a step down transformer. I use a very high quality one (rated for 1000+ watts) that has been working very well with other 110V Mesa's (Mark II and Mark IV). They never blew a fuse even after being left on for multiple hours.
Again, thanks a lot for any help on this. I really like this amp and would like to gig with it but unfortunately I've been struggling with this mysterious fuse issue...