11-28-2017, 01:38 PM
Alongside the rewinding, I had also started to clean up the chassis, scraping, scrubbing and derusting in a few spots.
The cans over the IF transformers were removed, allowing a new top cap wires to be brought out for the IF valves on the left side. At the right rear of the chassis, there is still a big hole where the electrolytics used to live. I found some motor caps of appropriate rating, made a clamp and fitted them in place:
Other wiring was replaced with new cloth covered wire, and I started working through the block capacitors. Here again, the repair man, many moons ago, had been at work. Some block caps had been clipped out of circuit and new caps added. Wiring was returned to the factory positions once the blocks were rebuilt and replaced.
An experiment occurred to me - paper caps go bad due to moisture absorption, so I measured one taken from a block which indicated ~1 - 2 Megohms on the DMM, and then baked it in the oven for a while. On the DMM, at least, it appeared recovered, showing no leakage, and correct capacitance again. A proper high voltage test would make an interesting comparison, but it made me wonder if the entire block could be baked to effect a recovery, and how reliable it would be?
The cans over the IF transformers were removed, allowing a new top cap wires to be brought out for the IF valves on the left side. At the right rear of the chassis, there is still a big hole where the electrolytics used to live. I found some motor caps of appropriate rating, made a clamp and fitted them in place:
Other wiring was replaced with new cloth covered wire, and I started working through the block capacitors. Here again, the repair man, many moons ago, had been at work. Some block caps had been clipped out of circuit and new caps added. Wiring was returned to the factory positions once the blocks were rebuilt and replaced.
An experiment occurred to me - paper caps go bad due to moisture absorption, so I measured one taken from a block which indicated ~1 - 2 Megohms on the DMM, and then baked it in the oven for a while. On the DMM, at least, it appeared recovered, showing no leakage, and correct capacitance again. A proper high voltage test would make an interesting comparison, but it made me wonder if the entire block could be baked to effect a recovery, and how reliable it would be?
I don't hold with furniture that talks.
