1966 GE PortaColor Restoration

[jr_tech]

Post #22 in this thread shows a typical ripple for the 270 volt supply. I suspect the other supplies would be similar.

jr

[zeno]

First off IIRC C1 is a 105 deg C & the others are 85 deg C.
Look at the old C1. If you use a lower rated cap it will NOT last
long. The new C1 probably got stressed out when wired wrong &
is the cause of your ripple.
After the ripple is fixed next step is the vert so if you are ordering parts
you may want to order the vert tube. Should be cheap as its
pretty useless for other apps.

73 Zeno
LFOD !

[Dubis7]

C1 has already been swapped out for a new one, but I'll double check the temp rating on the one I used.

I also tried swapping in the vertical tube, no luck there.

I still have not replaced C3, and considering my HV is low and I'm still hearing sparking from around the horizontal section, I'm not sure my problem is originating directly in the vertical section.

I'm going to replace C3 over the next few days and see what changes. Worst case, C3 needs to be replaced anyway. I wonder if that didn't get damaged.

[Dubis7]

Okay, finally had some time to sit down and work on this.

C3 is replaced. I didn't notice any change in the vertical behavior, but I hooked up a source and it looks like the waviness is gone.

I've ordered a new C1. It turns out that the C1 I swapped in is a lower temperature rating than it expected, so I've sourced another and will see if that helps. Not sure it will, but maybe it will at least get rid of the buzzing that's come up.

I made another video to show where I am. https://youtu.be/gIrCuJHy9OQ

Any thoughts on what I should check next?

[jr_tech]

Does fine tuning help, or is that the best you can get the video? Are you on the correct channel?

jr

[user181]

Did this issue exist from get-go when you started working on the set, or did it arise at some point later?

[Dubis7]

Originally Posted by user181

Did this issue exist from get-go when you started working on the set, or did it arise at some point later?

There was audio buzz, but I had fixed it. The vertical issue is new since I replaced C2, the brightness didn't disappear at the middle of the control, and I believe the color issue I've noticed now is new.

Here's a video I took. I was able to fiddle a bit more with the fine tuning and get the picture stable. I'm noticing that the picture is actually off the edge of the screen horizontally, which is new (I used this exact computer with the tv before I started) and I'm seeing a line of color where there wasn't one before. https://youtu.be/oYJG5Czpvvo

I'm still waiting on a replacement for C1 to come in. I'm also going to see about swapping in new caps for C2A-C2C, since those could have been stressed when I miswired C1 before.

Any thoughts on where I should go next? Could a lot of these be related to stressed caps on C1 and C2?

[old_coot88]

On the color issue: the chroma signal is getting to the CRT, evidenced by your being able to vary it up and down with the color control. But the 3.58 reference signal appears to be missing (per your vid in post# 82). So apparently GE's (in)famous 'ringing crystal' circuit is not ringing. This could be from loss of the burst signal, bad tube, or possibly a bad crystal.

PortaColor gurus can no doubt pursue the issue further. Maybe somebody could post a full schematic and tube layout diagram.

[user181]

Is DaveWM still active in this forum? He's one of the PortaColor gurus. You might want to send him a DM.

[jr_tech]

Link to schematic from the first post of this thread:

https://drive.google.com/file/d/1q4d...aMPiHQKBL/view

jr

[Dubis7]

Originally Posted by user181

Is DaveWM still active in this forum? He's one of the PortaColor gurus. You might want to send him a DM.

I feel like I've seen him around. I'll see if I can connect with him.

How would I go about checking the ringing crystal circuit? Could that be related to my vertical issue, or am I looking at multiple broken things here?

[Electronic M]

nope, color and vertical are totally separate stages.

[Dubis7]

Originally Posted by Electronic M

nope, color and vertical are totally separate stages.

And here I was thinking it just needed some new filter caps in the beginning. This is turning into a fun puzzle after all.

[user181]

Consider getting a capacitor tester like I mentioned earlier.

[Dubis7]

I have one, actually. A Heathkit C3. I think I need probes for it, though.

I'll take a look. In the meantime, the caps finally came in. I'm gonna swap those in tomorrow. It's been a hectic weekend.