Vertical 'jitter' - Videokarma.org TV - Video

pearsonk · #1 02-14-2011, 03:26 PM

Help me with a problem please.
I have a '48 Stromberg-Carlson # TV-12, fully recapped & operational.
Works fine, except for a very, very slight vertical 'jitter' which is not
immediately noticeable - but becomes obvious if you try to watch a program.
Where is the problem? I can't locate it.
Thanks for any guidance.

chipper · #2 03-23-2011, 08:08 PM

HI; I had the same problem with my philco projector set and found out after looking over and over , that I had some cap connections touching and also found bits of solder here and there in the vertical section.

Findm-Keepm · #3 03-23-2011, 09:36 PM

Dunno if I can help, but I had an KCS-8? RCA with a jitter that drove me crazy. Problem was some increased value resistors between the vertical sync amp and the oscillator.

If your Stromberg is based on the Dumont RA-103, the schematic will look like the one I've attached. Check the three 10K resistors and the two caps hanging off them. They, as a circuit "clean up" the vertical sync for the oscillator. If your height and linearity are A-OK, I'd guess the problem to be among those resistors. RCA used 22K ohm resistors - I still have one of the bad ones hanging from a bench lamp mount above the workbench. It reads 34K, a wee bit out of tolerance.

Cheers,

pearsonk · #4 03-23-2011, 10:18 PM

Thanks for replies.
Yes Brian, its basically the Dumont 103 chassis. I'll definately check out
the resistors, probably will be a few weeks, I'm leaving tomorrow for awhile.
Will let you know.
thanks.......