Non ADA Gear > Amps

Mesa 50/50 lo power issue

(1/3) > >>

Soloist:
Hey all,
since I re-configured my rig I thought I would give the 50/50 another shot. First off it sounds great, way better than before. I simplified my rack a bit so the gain staging is much easier. The issue I am having is on lo power it sounds like a blown speaker on one side. I swapped the speakers leads and it moved to the other cab. Ok the speaker isn't the issue. It doesn't do it on hi power, so what do I need to do to fix the lo power setting?

Systematic Chaos:
I’ll send you the orig Boogie service schematics when I get home. I had the same issue with my old 50/50 in 2009 and the culprit was a faulty resistor in the fixed bias circuit.

*edit* here’s the doc: https://www.dropbox.com/s/tieq9t4izk4dz3c/5050%2BMod.pdf?dl=0

Soloist:
Thanks SC!  I figured you or MJMP would know. Had a feeling it was a resistor I just didn't know where. :bow:

Soloist:
Ok SC, after looking over the schematic I see 4 resistors in the fixed bias circuit.
R322
R201 10k
R241 47k
R242 68k
Any idea which one I need to replace? I was hoping that you remembered which you replaced.

Systematic Chaos:
IIRC it was R242 on mine. If I were you I take a MultiMeter and measure them all. Also measure R229 (220k, parallel to the Hi/Lo Pwr Switch).
Since I had my PCB out back then I ended up replacing all component with new and higher qual/spec ones ;-)

Navigation

[0] Message Index

[#] Next page