Heathkit GR-53A color TV

[Electronic M]

If you have a tuning eye type capacitor checker I'd recommend checking all lytic capacitors between the secondary of the power Xfmr and the vertical stage(also double check that none of the lytics are wired in backwards.). Check the B+ rectifiers for leakage if they are not tube also.
Heater-cathode shorts on tubes are also a potential source of AC leakage into the B+.

[Ralph S]

The PS doubler is working fine and all of the electrolytics along with the tubular caps are new. Before they were put in they were checked with an ESR meter and a capacitance bridge for correct and tight values. I tend to agree with you that the most suspicious site would be a heater to cathode short, but so far I haven't found it (or them). I've gone through the two major pc boards with a fine-tooth comb and haven't found anything out of the ordinary. Any other thoughts? Bear in mind that this set was assembled by a rank amateur a long time ago and I've already fixed an "arm's-full" of construction problems, but there may be more. Thanks for your comments.

[old_tv_nut]

Ok, my guess then is that the signal on the vertical is not related to the problem, except that it happens to be coming from the 60 Hz line.

I'd poke around the sync separator / amplifier (whatever's in that area) and maybe the AGC at this point. Can you post the schematic for the sync section?

[DaveWM]

I still think you should check the grounds, if there is a common ground for the deflection board (assuming it has a PCB) then a defect in the ground could see a beat freq with the vert vs AC , then share that with the horz (same ground on pcb) and get some modulation on the horz tube cathode. Power up the filaments on the deflection with a 6v battery and see if it goes away. On my hula it would take something like 10-15 seconds to work its way thru (a vert line would show a slow moving horz shift like a hum bar, but much slower).

[Ralph S]

Here's the AGC, Sync Sep and Vertical section of the Heathkit. If you need the Horizontal section, let me know. I'm going to take a look at the Horizontal section again this afternoon. If I stumble into something, I'll let you know.

[Electronic M]

A picture of the symptoms could also help...

[Ralph S]

Well, thank you to all who replied and if I had a live TV feed to videokarma, you'd see me knocking my head with my fist for not checking this first: it was the PCB grounds as Dave and others suggested. I had put a tight ground bond on the IF board several days ago and only checked the Video/Color and sound/sweep boards with an ohm meter at that time. But the moment I bonded the grounds to chassis on those two boards the problem was solved. What a relief! Now on to getting rid of the nasty cataract and getting the color setup spruced up. MANY THANKS AGAIN!!!

(PS: I'll try to get some pictures out tomorrow!)

[old_tv_nut]

Good! Onward...

[Ralph S]

As promised, here are two off-screen shots showing the present stage of the Heathkit GR-53A set. The bars are from a Sencore VG91 and the live shot is off the air from KABC news at 11:00 AM. I didn't adjust anything between the two shots. The cataract is very evident, but the picture in the center tells the story. Also, horizontal hum/weave is gone!!!

[DaveWM]

looking good

[Kevin Kuehn]

Looks nice. But I was hoping to get to see a picture of the whole TV.

[Ralph S]

Kevin it'll be a while before the set is put together and tweaked for best performance given that the CRT has to be decatted. In any case, you will be shocked to see what the cabinet is for this set. It'll make you wonder what the thinking was when the choice was made.....

[Ralph S]

The following is really aimed at Dave WM because he's the guru of cataract removal and because I wanted to include some pictures I think you all might find interesting.

I've pulled the CRT out of the chassis assembly in preparation for removing the cataract, but I wanted to send you some photos to confirm the type of resin used. I suspect that this was a "Zenith" type of construction. The first shot is the only label on the tube. Nothing says RCA. The second shot is the join of the safety glass, resin and faceplate. It was a very easy matter to run a short blade around the circumference of the tube, in the resin. The third shot is a piece of the stuff showing its crumbly texture. The fourth shot shows a screwdriver inserted next to the faceplate and pulling some of the resin away; no serious resistance! What do you think? I suspect that this is a candidate for the "guitar string" method.

[bluenorm]

that is an rca cataract

[old_tv_nut]

If you can find an EIA number on a label, that would tell you the maker.

http://www.triodeel.com/eiacode.htm

RCA 274
Zenith 343