[drh4683]

Got another hybrid going, a 4B25C19 from 71. Needed all new static convergence pots as the originals were seized. They were junk, lubricating them did nothing to free them up. Luckily I have a bunch of convergence boards that I was able to swap parts from. Did some choma alignment to get the color tracking back in line. Looks and works like brand new again. This is only a year older than the other set that looks similar to it, but the chassis is different. This is a rather odd chassis, there is a speprate "chroma control" on the side of the set, it takes place of the contrast control, then you have color commander on the front of the set, which is a ganged control for color and contrast. There is a specific order in which these controls must be set (by the user!) brightness must be very dim, then you advance the color commander, then adjust the chroma control. Once you have the chroma control set, you should not need to adjust it, only adjust the color commander. It was a detailed procedure explained in the service manual. It tell the service technician to make sure the owner fully understands this operation.

Basically, I dont think too many of these sets survived. Obviously most everything is gone today no matter what, but these sets didnt hold up 10 years, as the controls were improperly set and the crts were drivin too hard (exessive contrast, high bightness) and killed them. This set has a replacement sylvania crt from 4-7-77, so about 6 years of use and this set was done. I was surprised to see that someone acutally had the crt replaced in a set like this. Well, it works good today, thats the main thing.