630TS Lost the Vertical
 

OK guys. I've been asked to look this chassis over and see if I can find the problem. Well I can't.
The background is that it has been recapped and some of the resistors have been replaced. It did have vertical when first tried but then lost the vertical soon after. The Vertical Centering pot does move the trace up and down. The Vert. Lin. pot has little effect.
Here's what I did so far.
1) I checked out the Vert. Osc. and the Vert. Output transformers. Both ohmed out good.
2) I ohmed out the yoke and it checked good.
3) Checked the tubes in the Vert. section along with the tubes in the Sync section. All tested in the good range.
4) Traced all the components in the Vertical section to see if they went where they were supposed to along with their values. All looked good.
5) Checked and cleaned both the Height and Vert. Lin pots. Both checked good on the ohmmeter.
6) Did a through visual for shorts, solder blobs, etc.
7) Tapped on the chassis some but that didn't help either. :>).
Here's a picture and then a video of the situation.
Any ideas guys?

https://tvrestorerguy.com/wp-content.../100_0184a.jpg

And the YouTube video:

https://youtu.be/RyM6xCjcXiY

What about the hold pot ?

Yeah, that ohmed out good. It was cleaned too.

Got scope? Checking the waveforms against the schematic (if sams that early have waveforms) should reveal issues.

Another method is to connect the heater to the output tube grid...That will inject a 60Hz signal and give the output some drive. If the output works with injected drive then you can also do the same at the osc. grid to check whether the isue is in the coupling between osc and output or a lack of oscillation.

Better to couple it through a cap. Value not critical, .047 - .1 mf or so.

Guys,
I coupled the grid of the output tube to the heater and then did the same for the OSC. tube. I used a .047 cap as suggested.

The first picture shows without any heater coupling to the grid.
The second picture shows the Output tube.
The third picture shows the OSC. tube.

https://tvrestorerguy.com/wp-content.../100_0189a.jpg
https://tvrestorerguy.com/wp-content.../100_0188a.jpg
https://tvrestorerguy.com/wp-content.../100_0187a.jpg

Looks like when the heater is coupled to the grid of the OSC. tube I get the most Vertical.
I'm puzzled. I thought it would be greater vertical with the Output tube coupled.

I'm not electronically adept, but just wanted to chime in that when I acquired my restored 630 I had a heck of time getting the rear adjustments just right. It took a careful tweaking of all controls to keep the picture centered and steady. The "sync lock" thumbwheel control was particularly touchy. Once set it's been fine.

Joe,
Where is the "sync lock" thunbwheel" control?

It's on the rear chassis with the other controls. It's the small thumbwheel control that is positioned slightly higher than the rest of the controls. I believe towards the middle, right above the antenna input panel.

Where is this sync-lock control in the circuitry?

If I'm not mistaken that sync control is an aluminum square can with the adjusting screw in the center. I don't think it's on top it's on the under side of the chassis .

Yes... horizontal frequency slug B2, and the terminal strip below is "sync link"

jr

Vertical oscillator blocking transformer?

The control I was mentioning is on the back of the chassis directly above the antenna terminals. It's a thin control shaft with a thumb-wheel end. Here's a pic from the Net where you can easily see it:

Sorry, the antenna terminals are in the upper left, above the power transformer, the terminal strip by the ul sticker is the "sync link" strip, see my previous post.

jr