Hello,
A few days ago I bought a Mesa 50/50 Poweramp (The old version).
I took to a gig my band had just a day later after purchase, so I had just tried it out. (I bought it unseen).
I was kinda stressed out because we were running late and during soundcheck the speakercable popped out in the back which resulted in no sound. So I started tweaking the volume up and down. (Yes im a fool, I should have checked the cables first, but as I said I was stressed out and tired) and suddenly there were this "bzzzzzzz"-sound coming from the amp and it started to smell burnt.
I disconnected everything and borrowed a amp for the gig instead.
When I came home I changed the fuse and tried to power it up.
The fuse burned up ímmidietly when I switched over from standby.
Tried putting in a new fuse and just looked if the tubes were lightning up.
3 of 4 seemed ok, but the fourth were black.
I took that one out and tried again.
I came to the conclusion that 3 out of 4 tubes were f*up.
I opened it up and found that both Resistors R101 and R102 had burned up.
I desoldered the black stumps that were left of the resistors and cleaned
the board.
What I can see there are no evident damage to the traces or any other components that I can see. The board is a little bit black though, just were the resistors were.
I can get sound from the poweramp (both sides) using the only tube that didnt go, without the resistors.
So im guessing that the OT´s are ok? with them broken I wouldnt get any sound at all, right?
I have ordered new resistors to solder in but how can it work without them?
What does the R101 and R102 resistors do?
Heres a link to the schematic:
http://www.schematicheaven.com/boogieamps/boogie_5050.pdf
They are on the second page.
A few days ago I bought a Mesa 50/50 Poweramp (The old version).
I took to a gig my band had just a day later after purchase, so I had just tried it out. (I bought it unseen).
I was kinda stressed out because we were running late and during soundcheck the speakercable popped out in the back which resulted in no sound. So I started tweaking the volume up and down. (Yes im a fool, I should have checked the cables first, but as I said I was stressed out and tired) and suddenly there were this "bzzzzzzz"-sound coming from the amp and it started to smell burnt.
I disconnected everything and borrowed a amp for the gig instead.
When I came home I changed the fuse and tried to power it up.
The fuse burned up ímmidietly when I switched over from standby.
Tried putting in a new fuse and just looked if the tubes were lightning up.
3 of 4 seemed ok, but the fourth were black.
I took that one out and tried again.
I came to the conclusion that 3 out of 4 tubes were f*up.
I opened it up and found that both Resistors R101 and R102 had burned up.
I desoldered the black stumps that were left of the resistors and cleaned
the board.
What I can see there are no evident damage to the traces or any other components that I can see. The board is a little bit black though, just were the resistors were.
I can get sound from the poweramp (both sides) using the only tube that didnt go, without the resistors.
So im guessing that the OT´s are ok? with them broken I wouldnt get any sound at all, right?
I have ordered new resistors to solder in but how can it work without them?
What does the R101 and R102 resistors do?
Heres a link to the schematic:
http://www.schematicheaven.com/boogieamps/boogie_5050.pdf
They are on the second page.
