Starting work on the Sylvania 7140M

[heathkit tv]

All these difficulties makes me wonder how they were able to align/set up TVs at the factory. Imagine their having to do this accurately AND quickly. Yikes

[jeyurkon]

I meant to take the Wallace's in to work to scan today but forgot.

I'll look at the schematic when I get home tonight. I think the circuit is similar to my Sylvania and I think it was the tube acting as a variable reactance that had a very small grid leak causing the same problem that you're observing.

Actually in mine there were two causes. I also had an open video IF transformer, but enough signal was leaking through it to give me a distorted picture that looked like only a horizontal problem.

John

[Eric H]

Thanks John, the 6BF5 Video output tube is somewhat weak but I just checked it again and it's not all that bad, no shorts either.

I'm getting strong video but there is some horizontal ghosting that moves across the screen when I adjust the Horiz Hold coil, it never quite disappears before the picture loses sync, in either direction.

Otherwise I have a good stable picture, no rolling, no jitters, good sound, just split in two, it's dim though, I attribute that to the low HV which is about 10k with no load but drops as the brightness is brought up, I can see the picture well enough to see whats going on.

I'm poking around checking resistors and voltages today, so far everything looks really good.

I had the same problem on a Sonora I rebuilt, in that case it was the replacement Flyback had the polarity reversed on a winding that affected the pulse that affected the Phasing, I can't remember exactly how it worked but I had to reverse the connections to the winding to fix it.

Someone has replaced or tinkered with the Horiz Size Coil at some time, I could tell because of the spliced wires inside the HV cage.
I don't see how that would really affect it but I mention it just in case.

The .0005 cap C213 seems to be hooked to the wrong side of C211 according to the schematic,, it looked like that was factory wiring however, I tried it on both sides and it doesn't seem to matter much so I put it back like it was.

I'm having some difficulty understanding how the Phasing and Sync are related, i.e. what section should I be looking in to find the problem.

If anyone has any suggestions please chime in, here's a link to the schematic picture kindly provided by John.

http://vintagetvsets.com/schem/sylschem.jpg

I'll have to replace or cover the Yoke wires when I finally do get it working, they are so dry and brittle they kinked and cracked from all the moving around while removing the HV cover numerous times, it looks terrible, couldn't be avoided, just one of those things that happen on 60 year old sets.