68 Zenith 25" color console - Videokarma.org TV - Video

Adam · #1 07-08-2016, 01:59 PM

20Y1C48 chassis

Basically works. I see an occasional light or dark horizontal line flash across the screen, I've seen this before caused by a corroding connections in the CRT socket. And it has the green halo, not that noticeable with the set on. The tube was replaced in 71 and is good otherwise.

This is going to be my new front room set. It isn't an exact matching pair, but it looks like it belongs with the '66 Zenith console stereo I also have sitting out here. The TV I was using out here before is a '77 CCII console with a good chromacolor 23V tube, I'm thinking I'm might just swap the tube and socket from the '77 into the '68.

DaveWM · #2 07-08-2016, 05:30 PM

move the video out tube around and see if you can effect that problem. IIRC there was a note in the zenth service manual about cold solder joints to the video out.

zeno · #3 07-09-2016, 09:06 AM

The ends of the terminal strips would crack open & go
very int. Seemed most common on tin cans. Sometimes there
are also grounds along the strips & at the tube sockets.
Poke them with a screw driver & see if they move.

73 Zeno

Adam · #4 07-11-2016, 06:41 PM

Whatever was causing that, it somehow managed to fix itself

Except for the green halo the picture looks great, and the convergence and purity is spot on. I still think I want to eventually swap in that chromacolor tube out of that CCII 23V console, but I don't think I'll do it for a while.

Olorin67 · #5 07-11-2016, 09:12 PM

If you do swap tubes, I'd be interested in the old one. I have a 66 or '67 Zenith metal tabletop with a rather weak CRT.

Adam · #6 07-13-2016, 11:25 AM

The hard part would be getting it to you. Is anyone is planning a TV run between MI and WI this summer?

Electronic M · #7 07-13-2016, 01:19 PM

If someone does I have a set that needs to get to it's buyer in MI....

Adam · #8 07-15-2016, 03:04 PM

I'm going to try this tube swap. The new tube is a 23VCMP22. Does anybody need any parts off of that 25JC49 chassis? Or want the cabinet? Otherwise my plan is to keep the chassis for parts and dump the cabinet.

Electronic M · #9 07-15-2016, 06:21 PM

Why not do a full CRT swap and keep both sets usable?....And while your at it you might want to unplug your cat or have it exorcised.

Adam · #10 07-15-2016, 07:03 PM

I bought 6 consoles in the past 3 months. I'm up to a total of 14 consoles! And that one is a little water damaged on the top, and it's a cabinet style I don't like much anyway.

Adam · #11 07-15-2016, 10:25 PM

Well now I know the 23VCMP22 for 25GP22 swap works! That problem I was having before came back, but I found out it was just being caused by a dirty IF tube socket.

Adam · #12 07-16-2016, 11:18 AM

So everything was working great, but I hadn't put that metal enclosure around the back of the CRT. (What is the point of those things anyway, except to hold the auto degauss coil and make it really hard to put in a CRT?)

And the new tube was a little wider than the original because it has one of those metal bands around it, where the original didn't. I wound up removing two of those little pieces of cushion material on the corners of the surround/mask on one side to get the tube in, but after that everything fit great.

But when I went to try to side that metal enclosure in there was no room for it to slide between the CRT and the surround/mask it fits into on that one side. After messing around with it for several hours with no luck, I finally just cut off most of the front edge of that enclosure on one side (just the first 1" or so where it slides to the side of the CRT on that one side), and that got it to fit.

By that time it was pretty late and I was tired. I wasn't looking at a clock but it had to be between 4:30-5AM because the Night Gallery was on. So I was really tired and I got it all back together, but forgot to connect up the HV. I turned the set on, and that HV lead sitting on the chassis arcs to something … and whatever it took out is keeping me from getting H or V sync.

(From what it looks like the oscillators are fine, but the sync pluses aren't getting to either the H or the V osc)

Then I got out a schematic, sat down on the couch to look at it, and fell asleep...

Adam · #13 07-16-2016, 02:42 PM

I must have really been out of it late last night. All that sync trouble was just a tube that got pulled out of the socket a little.

Remaining problems are that convergence needs to be redone, and those horizontal lines are back. It seems to be responding to shaking the tuner. I lubricated the gears in the tuner last night so now it's actually possible to change the channel (before the uhf was frozen stuck). I'll take the tuner back out and clean the contacts inside.

Sometimes you really shouldn't work on stuff after you get tired. Last night I knocked into a picture on the wall which fell and put a dent in the top of the otherwise nearly perfect cabinet of my 66 Zenith console stereo (I was holding a CRT at the time so I couldn't grab the picture as it was sliding down. And in the process of doing that I pulled out the power cord on this video modulator/switch I use and now I have to resolder the socket it plugs into.

consoleguy67 · #14 07-16-2016, 05:42 PM

Get some sleep.

Adam · #15 07-16-2016, 06:14 PM

It works, no more green halo, no more mysterious horiz lines, good convergence…the channel # light just burned out, but that's easy to change… I'm going to bed early tonight

Crappy cell phone pics, my digital camera just quit (says it's the memory card, but I don't have another one to test).