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Hi all, been a member for a while but don't think I've ever posted - just reading all this great stuff. ;-)
Well, a buddy of mine asked me to look at his BH LG that doesn't produce any output - not a peep. Tubes light up, power is ok, everything seems fine - tubes have been swapped with known good ones - so that's not it. His input and output jacks are all ok (did cont checks with cables plugged in). Went through the thing with a DMM and did a voltage check: on the second gain stage plate I'm getting 10v at the plate - First stage was approx 174v and all other voltages all looked fine (tubes and Power supply - B+ through B+5). I wrote them down on the schematic but forgot it at home - I'll post them when I get home. When I say "fine", I should say without a reference they seemed reasonable for an amp of this design. That said, I was wondering if there were any reference voltages that I can check against since they aren't on the schematics or the layouts I have (PCB).
I'm going to try replacing the plate resistor (R.8) but I'm wondering if there is anything else that could have caused this situation that I ought to be on the lookout for.
My experience level is pretty much beginner to maybe advanced beginner - I've built 2 tube amps (both work great), an AX84 HO kit and a "custom" Firefly on tag-board (pretty much scratch built), third is a 5E3 (which is in progress) plus a few pedals. I think I have a pretty good grasp of the basics.
Thanks for any help,
Jim
Well, a buddy of mine asked me to look at his BH LG that doesn't produce any output - not a peep. Tubes light up, power is ok, everything seems fine - tubes have been swapped with known good ones - so that's not it. His input and output jacks are all ok (did cont checks with cables plugged in). Went through the thing with a DMM and did a voltage check: on the second gain stage plate I'm getting 10v at the plate - First stage was approx 174v and all other voltages all looked fine (tubes and Power supply - B+ through B+5). I wrote them down on the schematic but forgot it at home - I'll post them when I get home. When I say "fine", I should say without a reference they seemed reasonable for an amp of this design. That said, I was wondering if there were any reference voltages that I can check against since they aren't on the schematics or the layouts I have (PCB).
I'm going to try replacing the plate resistor (R.8) but I'm wondering if there is anything else that could have caused this situation that I ought to be on the lookout for.
My experience level is pretty much beginner to maybe advanced beginner - I've built 2 tube amps (both work great), an AX84 HO kit and a "custom" Firefly on tag-board (pretty much scratch built), third is a 5E3 (which is in progress) plus a few pedals. I think I have a pretty good grasp of the basics.
Thanks for any help,
Jim
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