20 inch GE CTC166CS chassis red smearing but strong CRT

[MRX37]

I found what is basically an RCA Colortrak TV, only it has a GE badge on it. It was made in February 1992, and is a CTC 166 CS chassis. So basically an early Thomson built rebadged RCA set.

I am pretty sure this set is a low hour set. I do not have a CRT tester, but the CRT produces a good picture even with the drive and bias controls set to absolute minimum. The inside of the set was relatively clean, not very much dust on the HV anode lead, and with the brightness and contrast set at their midpoints I have a nice bright image with the bias controls turned all the way down, and the drive controls turned up maybe 1/8th of a turn if that. Other than that I have just made slight adjustments to the G2 and focus controls.


So here is the problem: Red or red/orange colors are a little bit smeared. It's not much smearing, but it is noticeable. Color level makes it worse and I know its not my video source because if I turn up the CRT drive controls, the onscreen menus start to smear.

I have seen this before on CTC 158 chassis sets (RCA Colortrak 2000) and I don't think the issue is CRT related. I'm wondering if something on the chassis has gone out of spec.

[old_tv_nut]

Does this set have separate G2 and bias controls?

[MRX37]

Originally Posted by old_tv_nut

Does this set have separate G2 and bias controls?

Yes.

By the way, picture of the smearing I am dealing with:



It's not much but it is enough to bother me.

[old_tv_nut]

Hard to tell from that picture - does it look ragged and changing like a torn fabric and comes or goes abruptly as the color is turned up, or stationary, intensity varies smoothly with color control and gradually fades out to the right?

If ragged, it's a bias/G2 problem, possibly fix by going through proper G2 and bias set-up procedure. I suspect this isn't it, because the white rectangle isn't showing it. Edit: try turning brightness and contrast to max to see if it appears on the white rectangle.

If stationary and gradually fades, it's a chroma smear. Maybe can be improved a bit by fine tuning.

It looks to me like the blue part is smeared too, which would also say a chroma smear.

[MRX37]

I'm leaning towards Chroma smear. It's not ragged at all. No, the smearing is smooth, changes with color level.

Brightness and contrast at max do not affect the white rectangle.

I should also note that I am running an S-Video signal, so the tuner is not involved at all.

[MRX37]

I realized I am being a little stupid about this. I have a good camera and a YouTube account so why don't I just show what's going on rather than try and describe it? Just need to find some commercials so as not to trigger the Copyright fascists...

https://youtu.be/NBcuLOPp1og

[old_tv_nut]

Look at 0:32.

The orange bar is dark on the left edge and smears to the right on the right edge.

I'd say this is a combination of the normal low bandwidth of chroma plus a mismatch of chroma and luma delay. The delay mismatch probably arises in the cable box (or whatever your source is), which doesn't have a luma delay to match the chroma bandwidth, and not in the TV.

At 0:40, it's also obvious in the logo in the video just above the menu.

[MRX37]

I could believe that, but it shows up in the onscreen menus (not to the same degree unless I turn the drive controls up)

I mean if that's just normal for this chassis I can live with it, but I'll probably never find another one of these in this good of shape, so I just want to make sure its working at its best to have a good reminder of what a properly calibrated CRT looks like.

[MRX37]

There is another thing that is not a problem right now, but could be a problem in the future. I need to add some context here.

I am more familiar with the CTC 158 chassis. You unplug one of those, plug it back in and turn it on, and it starts autoprogramming because it lost the channel information. This CTC 166 remembers its channel info. Great!

It also has an on screen clock that displays accurate time. Great!

Uh, wait... that means this TV has a real time clock, which as far as I know should be powered by a battery...

...A 28 year old battery...

Now I have looked at the chassis. I have not had it out of the set, but I have looked at it and seen nothing like a battery. If there is one in this set, maybe I should know about it before it decides to leak and destroy traces on the circuit board.

[zeno]

The smear looks like it may be normal or just a little off. That means
it will be tough to find. If you take a pix of the chassis something
may come to mind.
The clock probably uses a big cap to hold time. Batteries can surprise
you. I had an old Zenith R472 series clock radio sitting for years. My
sis needed one so I cleaned it up & test ran it a few days. It sat a day or two
unplugged & when it came up the clock was right ! Not bad for a
40 yr old battery

73 Zeno
LFOD !

[Electronic M]

Some batteries look sort of like capacitor or were primative super capacitors. Oftentimes they will have unusually high capacitance like 100000uF or xF listed... having a schematic or service manual makes IDing parts like that less of a guessing game.

[liammc00]

This thread remained me that I have an RCA console tv from 1989 that needs to be fixed. The tv no longer powers up. I have not done any work on it yet. The crt in mine is little weak but still makes a very good picture when it was working

[old_tv_nut]

Originally Posted by MRX37

I could believe that, but it shows up in the onscreen menus (not to the same degree unless I turn the drive controls up)

I mean if that's just normal for this chassis I can live with it, but I'll probably never find another one of these in this good of shape, so I just want to make sure its working at its best to have a good reminder of what a properly calibrated CRT looks like.

I don't see it in the COLOR and BRIGHTNESS menus you popped up in the video. The set's on-screen menus(not those from your cable box) are generated by RGB signals, I believe, and can only have small color fringing due to misconvergence, nothing due to chroma smear/delay.

[MRX37]

Originally Posted by old_tv_nut

I don't see it in the COLOR and BRIGHTNESS menus you popped up in the video. The set's on-screen menus(not those from your cable box) are generated by RGB signals, I believe, and can only have small color fringing due to misconvergence, nothing due to chroma smear/delay.

Then what do you make of this?

[old_tv_nut]

OK - that's obviously visible. At this point, I'm out of guesses. A schematic might help.