I will ask in this thread before starting a new one.
I was able to repair the coil ... it was probably a replacement coil
that never worked at all, resulting in the set being retired. This is
because it looked never heated and the one nut holding it was missing and
the other loose. The HV winding had never been properly stripped and
soldered. I hope that is all that was wrong with it.
After a complete electrolytic and paper recap it works well,
with good raster geometry, brightness, and a passable picture.
The alignment might be a tad imperfect.
Edit: I found that a Rider's does exist, Vol. 4. A photo of one schematic page
was posted by Banderson in a thread on an Emerson:
http://www.videokarma.org/showthread...hlight=emerson
This is for the 639, which has the same sweep circuits. Does it have
waveforms?
I had to replace zero resistors. All controls on the back and
the two hold controls need to be near center. The only thing
is that the two hold controls are rather sensitive. Once set and
at constant line voltage they are quite stable. But if the line
voltage changes a lot they need resetting. A check with a 'scope seems
in order ... but since it works OK I really have nothing
go on. Sam's has no scope pictures. I can find
no Rider's.
Does anyone else have any more info on these sets?