Found a Videodyne on CL

[Eric H]

I've been working on this slowly but steadily, it's completely recapped but there are a few caps I just tacked in for diagnostic purposes and still need to restuff in the original paper sleeves.

The set was having some vertical issues, sometimes working, sometimes jittering all over the place and folding over, also the vertical output tube was overheating and a 22k resistor to the Sync tube (one I had already replaced) was getting hot enough to discolor.

I replaced the Vert Hold pot that was very flaky, that helped some but it was still having issues, they got worse after it ran a while.

Did some voltage checks and found some serious discrepancies in the Vertical section, that turned out to be an open winding in the Vert Blocking Transformer, tacked in a new (but incorrect) one and it started working very well. NOS Stancor transformer is on order, also some NOS Allen Bradley 1 meg resistors to replace a couple that are more than 50% high.

Here's a short video showing it malfunctioning.

And a picture showing it after subbing the bad transformer.The transformer I used is the wrong part number but is probably close enough I could have gotten away with leaving it, however the correct part (Stancor A-8111) was easy to find and cheap so might as well do it right.




The temporary transformer install, all the old paper caps here except the dangling one have been restuffed, the yellow caps and the blue electrolytics will be restuffed inside the original sleeves before it's done.
I had to dig up four 1949 era Sprague .1@600 caps to replace some that had been replaced way back in the sets history, I could have restuffed those I guess but I decided to use the type it left the factory with.
All the OEM caps in this were Sprague, none were Bumblebees or Black Beauties, that's good because they would have been hard/impossible to restuff.

[Eric H]

I'm calling the chassis done, I think the chassis is working as well as can be
expected.

I rewired the CRT socket using OEM style cloth covered wire in the correct (as far as I could tell) colors. The old wiring was so cracked and brittle it was shorting to the chassis where it came through the hole.
I also took the focus coil apart and replaced the wiring to it because it was just as bad.

Before


After ( I put all the rivets back in the base after I was sure it was all correct)


After rewiring the CRT socket I was having a problem with a dark bar rolling through the picture and unstable sync. It turned out to be something with the 6AG7 Video Output tube, maybe a bad connection or a bit of solder wedged under the socket, I just pulled it out and plugged it in a few times and it cleared up and became rock solid, the tube is new.

The General Electric 10BP4 that came with the set is very bright and sharp, it had some bad connections in the base but I re-soldered them and it's fine now.

Now I need to work on the cabinet and figure out what to do about the missing CRT bezel. I have a generic 10" mask that I'll probably use until I can find the correct part.

Very short video of it working posted here: https://www.youtube.com/watch?v=leoliK0yhBs