Cautiously optimistic that I will be successful, this is hopefully my first post to chronicle a complete rebuild on one of these beauties.
Between a non-working example and a pure parts carcass I am hoping that one functioning amp will result. The non-working unit didn't look too bad, but a clipped off power cord was not a good sign. Digging into it unfortunately has been pretty depressing, with soot everywhere, boards that are pretty toasted, butchered wiring, and missing connectors with wires soldered directly to pins (which seems to be amazingly common).
The external panels aren't bad, but there has been quite a bit of corrosion on the chassis. The donor unit had no panels (except for a top panel that I passed along to member Vigman), missing outputs, cut off input pot shafts (!), an unbelievable amount of dirt and what appeared to be a small rodent skeleton.
Surprisingly the boards on the parts carcass seem to be in better shape than those in the complete unit, so they will be the ones rebuilt.
My plan is to refurbish every square inch, so I am starting with possibly the scariest portion- the heatsink and TO-3 sockets. Several emitter resistors had been sloppily replaced and thermal grease slathered everywhere, so out it all came.
I have acquired the .33 ohm BPR series resistors as noted by Echowars in a posting elsewhere and a supply of Mil-spec Tefzel and tinned copper wire to lace everything back up. These first photos are of the cleaned up heatsink and tediously de-soldered and cleaned TO-3 sockets back in place:
This heatsink is a little rough, but unfortunately the sink on the donor unit was even worse (that was the end it appeared to be dropped on).
More to follow on this long-term project...
Herb
Between a non-working example and a pure parts carcass I am hoping that one functioning amp will result. The non-working unit didn't look too bad, but a clipped off power cord was not a good sign. Digging into it unfortunately has been pretty depressing, with soot everywhere, boards that are pretty toasted, butchered wiring, and missing connectors with wires soldered directly to pins (which seems to be amazingly common).
The external panels aren't bad, but there has been quite a bit of corrosion on the chassis. The donor unit had no panels (except for a top panel that I passed along to member Vigman), missing outputs, cut off input pot shafts (!), an unbelievable amount of dirt and what appeared to be a small rodent skeleton.
Surprisingly the boards on the parts carcass seem to be in better shape than those in the complete unit, so they will be the ones rebuilt.
My plan is to refurbish every square inch, so I am starting with possibly the scariest portion- the heatsink and TO-3 sockets. Several emitter resistors had been sloppily replaced and thermal grease slathered everywhere, so out it all came.
I have acquired the .33 ohm BPR series resistors as noted by Echowars in a posting elsewhere and a supply of Mil-spec Tefzel and tinned copper wire to lace everything back up. These first photos are of the cleaned up heatsink and tediously de-soldered and cleaned TO-3 sockets back in place:
This heatsink is a little rough, but unfortunately the sink on the donor unit was even worse (that was the end it appeared to be dropped on).
More to follow on this long-term project...
Herb