A'right, some progress. Spent the day familiarizing myself with the set and figuring out what capacitors I'll need to order.
Started by taking a look at the focus control... it made nasty crunching noises when turned, and on opening, my suspicions were confirmed - it's burned up, as is common with some designs.
How likely am I to find an exact replacement? This is a dual-control with brightness. Rear control is 50K 1/2 watt, focus part (front) is 2500 ohms, 2 watt. Clarostat 25B889. Can always mount focus somewhere else on the rear of the chassis, but would be nice to retain it by the front knob where labelled.
There are also two sand resistors... as is the case with most, the leads are corroded and this one (while it still measured OK) fell apart when I looked at it funny. I didn't have the required value for the other one on hand, I'll have to order it.
Whoever replaced the flyback did some bodgery, and there was a half-baked attempt at squelching some arcs with electrical tape on the inside of the HV cage... Likely because the rectifier cap lead had a terrible solder joint with pointy stray wires everywhere. After unsoldering, there was enough folded/bunched up wire to make it long enough to reach again.... Nice clean and smooth joint now, and also added some heatshrink for good measure since the insulation on the lead was too short.
No, I didn't solder while it was connected to the rectifier... You can see the allen key I clamped to the chassis to hold the HV lead ring while soldering.
More flyback bodgery. Looks like somebody miscalculated wire length; those aren't original wires, so I'll clean that up at some point.
Another interesting thing... these piggy-backed fuses:
I could see this if a homeowner was too lazy to unsolder a fuse and just put a new good one in parallel... but both of these fuses measure good. Any idea why this might have been done?
Another interesting thing is that the doorknob cap under the rectifier isn't really connected to anything... it's bolted to the corona guard ring/mount for the HV rectifier, but that is isolated and just floats. Huh?
I'll also have to take a look at the flyback mounting... the transformer is kinda squished in in an odd position and the replacer bent the cage when replacing it to make it fit. Looks like it might be possible to neaten up if I reorganize the inside of the HV cage a little bit...
