GE Roundie Issue

[tvcollector]

I've noticed this problem is starting to develop with my GE roundie.. Color bar squiggly lines.. Sometimes don't appear at all. Sometimes goes away completely when adjusting the antenna.. When cold power up the next day, they are back.. Seems like the better the reception is the better.. In white screens they appear, depending on where and how bright the screen is, is where it appears.. Where the color bars are makes that part of the screen green.. I haven't looked into yet.. Thought I would post first... Here's youtube video to see the symptoms...

https://www.youtube.com/watch?v=8b6H...ature=youtu.be

[Penthode]

Looks like it may be due to IF harmonic radiation. It looks like it is worst on peak whites which coincides with minimum carrier.

Try a different rf channel (channel 3 vs 4) and ensure the antenna connection is properly terminated and the 75 ohm coax to balanced 300 ohm balun is okay. It may help to move and rearrange the antenna lead to minimize this.

Also check all grounds around the IF and RF connections in the set and ensure the IF RCA connector to the tuner is tight.

I'd try this first before investigating further. Good luck finding the issue!

[tvcollector]

I think it's something loose.. A couple of knocks on the bottom made it go completely away.. Perhaps a tube on the color board...

[zeno]

Penthode has good ideas.
GE was famous for crimping on RCA jacks & tons of
them went bad especially the UHF IF link. Light tapping,
moving things etc should smoke it out. It does sure
look IF related. Cold joints, loose screw, dirty tube socket or pins,
bad tube & poor grounds on shields. PCB to chassis grounds also.

BTW IF cable probably soldered on the tuner. If you are not careful
you can tear the jack out of the tuner. Heat it & gently rock & twist.
When it moves turn & lift at same time. The center pin is the perp.

73 Zeno
LFOD !

[oldtvman]

Check the coaxial cable between the V tuner and the IF section. Wiggle it and see if it's a broken ground.

[tvcollector]

Hmmm.. I'll have to check it out.. I would literally have to re arrange the room to get the damn thing out of it's spot right now.. And it seems to be better after I knocked on the bottom of it, sometimes when I turn it on at will be back, but seems to go right away... I'll report back when I get to it...

[reeferman]

Originally Posted by tvcollector

Hmmm.. I'll have to check it out.. I would literally have to re arrange the room to get the damn thing out of it's spot right now.. And it seems to be better after I knocked on the bottom of it, sometimes when I turn it on at will be back, but seems to go right away... I'll report back when I get to it...

Ahh, the joys of owning an old roundie (rearranging the room, that is).

[DavGoodlin]

Is that a chassis CB21, not the CA (almost a CTC15 clone save for a few compactrons) from the year before? Im getting one next month for working on two RCA chassis.

Having memory of working on the 67-69 GE color chassis, cant wait to see what those interesting designs evolved from.

I will photo the IF link cable attachments since Ill have it apart to move it around, by myself as usual.

[tvcollector]

I'm don't think it's a clone.. The sweep board is on the opposite side.. It's a CB chassis CB21544 to be exact...

[DaveWM]

dirty pins and sockets on chroma board can result in very odd vertical color bars as well on that model, also small neon bulb can cause issues. Lots of wafer coils all over the place, easy to mess up with over zealous cleaning.

[dieseljeep]

Originally Posted by DavGoodlin

Is that a chassis CB21, not the CA (almost a CTC15 clone save for a few compactrons) from the year before? Im getting one next month for working on two RCA chassis.

Having memory of working on the 67-69 GE color chassis, cant wait to see what those interesting designs evolved from.

I will photo the IF link cable attachments since Ill have it apart to move it around, by myself as usual.

I had two of those dogs, both freebees, scrapped them both. Bad flybacks.
One was a low hours set an had an original RCA HiLite CRT. Used the CRT in a Zenith 24NC38. The picture on that set was better than it was new. Zenith didn't make a very good roundie.
The color circuit in that GE is similar to the PortaColor, only different tubes. Their Crystal Ringer circuit.