Mighty Monarch of The Air

[VintagePC]

Originally Posted by Electronic M

Vintagepc, I believe that this is not a color TV so it should not have purity or convergence adjustments.

Whoops... 's what I get for posting/following several threads at once

[old_coot88]

Originally Posted by VintagePC

Whoops... 's what I get for posting/following several threads at once

Heh.. I was kinda wunnerin' how the saga was gonna play out.


oc(Bill)

[vts1134]

Got the new transformer in the set and it gives deflection but not a full picture. It did bring the horizontal picture back to the center again. Even though it was not a full height picture it did for the first time look "correct." It might be because I could see scan lines for the first time, or because the picture was horizontally aligned, or it could just all be in my head. I did try adjusting the vertical hold control, the vertical linearity control, and the vertical size control, all to no avail. The transformer I used was a Stancor model a-8122. The turn ratio was 1:4.2. The primary and secondary impedance was a bit different on the replacement than the schematics showed on the original. The original was 160 and 1,300 and the replacement was 170 and 940. Could the transformer still be the problem or is it time to look elsewhere?

[VintagePC]

Do the vertical controls do absolutely nothing to change the bar, or just that they don't get it to a proper height?

You don't mention it, but I assume you tried the lead swap on one of the transformer windings to check if the phasing was right?

If you did, it's probably time to start looking elsewhere; you've got "partial" vertical, as opposed to flat-out no vertical. That would suggest an out-of-spec component - time to start ohming out the resistors in, and before, the vertical section to see if any have gone high if you haven't already done so. If those all check out fine, then it can shift the focus back to the transformer; less of a headache that way than trying to source an exact match and finding it still doesn't work.

Are you able to borrow or access an oscilloscope? Those can come in handy when trying to figure out the problem, since the actual shape and tracing back of the waveforms can point to the cause relatively quickly (i.e. if the problem is caused by the vertical section, or the result of something before) ... but it can be done without.

[vts1134]

Honestly I hadn't tried swapping the leads on the transformer. I guess my assumption was that if I wired it incorrectly that I would have no deflection at all. I'll try that first tonight. Thank you for taking the time to point out the painfully obvious, sometimes(hopefully THIS time) it helps.

[VintagePC]

Originally Posted by vts1134

Honestly I hadn't tried swapping the leads on the transformer. I guess my assumption was that if I wired it incorrectly that I would have no deflection at all. I'll try that first tonight. Thank you for taking the time to point out the painfully obvious, sometimes(hopefully THIS time) it helps.

Only because it happened to me when I re-wound the coil on my own radio. It didn't work well at first (though I could hear the output of a spark gap transmitter), but swapping the leads made a world of difference... so it's my mistake that you're learning from

[vts1134]

Switched the leads on the secondary of the transformer and it had little effect. The vertical was the same size. The only difference was the image was again shifted to the right of the screen. I switched the leads back and the image was centered. I did take v13 to a shop to test it and it passed, although the guy admitted that he hadn't used his tester in quite some time so it may have been way out of calibration. There is another shop in town that I know I can trust if I take the tube there to test it so I may do that. He may be able to give some advice if it passes, and sell me another one if it fails. If every thing checks out there it's time to move on.

I do have access to a scope btw so if there is some tests I can run with it to narrow my search down before I start checking every capacitor and resistor that would be fantastic.