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I'm in the middle of refurbishing a 1969 H-182, thanks to advice from George and Fred. So far, it'sgone well. I replaced all the capacitors in the power supply as well as on all 10 pre-amp boards, audio delay board, and the brush/cymbal board. The original main amp is still under construction. To test my progress so far, Itried an un-restored main amp. Already the difference is incredible, not to mention my amazement that my work on the power supply didn't let any of the smoke out. All the vibrato/non-vibrato pre-amps and the pedal pre-amp are working fine, but I've got a problem with the percussion pre-amp. The only sound any of the percussion tabs produce is a 'pop' each time percussion is triggered.</P>
George mentioned before in another thread that I should change the plate load resistors in addition to all the electrolytics in the main amp. I'm not really certain which are the plate load resistors because the circuit shown in the schematic is somewhat different from the examples I've found. I think I'm looking at the correct ones (R354 &R355 in channel A; R381 & R382 in channel B; R409 & R410 in Bass channel), but I'd appreciate any input before I start changing parts.</P>
I'm also a little confused about the value of a damaged ceramic disc capacitor in the main amp. C366 in the Bass channel is shown on the schematic as "20/50V" but the value marked on the original part is ".02". Any advice here would be aprreciated as well.</P>