It's a CTC 158B chassis. It was clogged with dust inside, so I cleaned that out. Someone also messed with the focus control. I readjusted that and it has that same Colortrak picture that I remember so fondly.

After I get it hooked up, I'll snap a pic of it. It looks a bit different from my old Colortrak 2000, but the screen and picture are the same. :D

Can't wait to see it, those sets really did perform well. Glad you found it!

http://i119.photobucket.com/albums/o121/mrx3750/RCAcolortrak2000.jpg

The camera flash doesn't do the TV's picture justice.

No tinted picrture with the color down. No color bleeding with the color maxed out. Crosshatch pattern shows almost perfect convergence, and unlike my last Colortrak 2000, this one doesn't have a single nick or scratch in the screen!

Nice find from the '90's. I've had many of these pass through here and they are generally good sets. Probably the last decent sets to bear the RCA name. Those Thomson CRT's usually hold up well; unlike Zenith tubes from the same time period. There is a transistor (Q901 luminance driver, IIRC) that I've seen fail. Also, I've seen bad vertical IC's, bad caps, power supply problems, an occasional flyback failure, etc. on these. Nothing that does not happen to any other set. I had the 27" version of this set that played perfect for years after a HOT and flyback replacement. In fact, it was playing fine when I got rid of it.

I mentioned that I used to have one of these. the one I had was bought new in 1991, and it never gave me or my mom much trouble. I think it was repaired once because of a sound issue. The only reason I sold it was because the picture was tilted slightly (bonded yoke... yay), and the screen had a small nick in it.

I've seen 90's RCA's hold up pretty well. Found an RCA XL 100 from 1995 that had a like new picture. I managed to sell it not 5 hours after I listed it for sale.

That was a good set. I recall seeing those in car dealerships, hotels, restaurants and other public places around here where they were run hard. The Thompson CRTs did hold up very well. If anything, they were equal or better than the 80s RCA tubes.

Should last a long time! If it has any Sanyo caps used for the smaller values I'd change em out. Like the Toshiba sets from the same time, these sets seem plagued with these caps. Some batches were fine, though.

Um, one picture flaw I've noticed. I've seen it alot on older TV's. Dark text on a light colored background smears on this TV. It makes a faint line all the way across the screen. Can anything be done about this? It's not color bleeding. The CRT is still bright and very sharp.

If it has a sharpness control, turn that down (closer to off) also, I've noticed a similar thing happen on sets with little or no DC restoration (which the ctc-158 certainly has) where the dark text gets washed out by the high contrast areas of the raster.

Just a hunch, but back off the contrast a bit and see if it helps. One of the video circuits may have low drive.

If it has a sharpness control, turn that down (closer to off) also, I've noticed a similar thing happen on sets with little or no DC restoration (which the ctc-158 certainly has) where the dark text gets washed out by the high contrast areas of the raster.

Just a hunch, but back off the contrast a bit and see if it helps. One of the video circuits may have low drive.

I'm already sure backing off the contrast will help. In fact, I wonder why it's set uip to 3/4 of the way by default? It was set at that on my original Colortrak too.

What would cause a video circuit to have low drive? Bad caps? I see this type of smearing on a lot of older TV's...

I've seen the smearing too, I try not to pay attention but sometimes it looks bad. I notice it on my '75 GE 19CD chassis set and a few others, Zenith sets don't have much of an issue with it. Other than that, the picture is great. Great picture on the RCA by the way. Very nice find, these are usually all beat up and half dead by now. This one seems to have had a good life.

Heh, it could have been cleaned more... the inside was nightmarishly filthy!

So, apart from playing with the contrast, what can be done about the smearing?

I really don't think there is much that can be done. If so, it's out of my experience range. I would start at I.F and check through the video output section. Just a guess. Maybe there are some parts that could be brought into a closer tolerance.

The most practical way would be with a 'scope and a signal generator and trace through the IF and video circuits to see if there is any "junk" on the signal. Frankly, the only way I'd go to that trouble would be if the problem was severe enough to bug me.

The smearing is probably all the old caps in there, most of them lose capacitance over the years. A full recap might fix the smearing and would most definitely improve the picture. I notice it on a lot of old tv's too.

The smearing is probably all the old caps in there, most of them lose capacitance over the years. A full recap might fix the smearing and would most definitely improve the picture. I notice it on a lot of old tv's too.

This is what I'm thinking too, but I wanted confirmation before I start shotgunning caps.

I took the chassis out to start checking caps, and I'm glad I did. I haven't found any bad or even marginal caps yet, but some weird part on the board broke off.

This part kinda looks like a disc cap. It's situated in the power section, between the fuse and where the degaussing coil plugs in. I noticed that the leads on it looked like they were detaching. When I touched it, the metal disc detached from the leads. I tried to solder the leads back on, and the disc broke in half due to the heat.

It looks like a simple metal disc. My ohmmeter didn't read any significant resistance through it. Could I just solder the two leads together to bridge the connection, or is this some kind of important part?

PS: The metal disc has a number on it: 100- 0/A A170D

Umm....Degaussing thermistor? Just a guess. It may not show resistance since its open until the degauss circuit kicks in at which point it gains resistance and then dies down with temperature.

Or not. Pic?

000

Umm....Degaussing thermistor? Just a guess. It may not show resistance since its open until the degauss circuit kicks in at which point it gains resistance and then dies down with temperature.

Or not. Pic?

Here's a (crappy) pic of the disc. My camera does NOT take good pics of small objects.

http://i119.photobucket.com/albums/o121/mrx3750/disc1.jpg

And here's a shot of the board with an arrow showing where the disc came from.

http://i119.photobucket.com/albums/o121/mrx3750/RCAspot.jpg

EDIT: Er, Andy, I already cracked it... now what?

If it's the degaussing thermistor, can I just use one from one of the TV chassis's I have lying around? I have several boards for 19" and larger TV's, or does the CTC 158B chassis need some kind of special thermistor?

Try and either look at the disc for a rating or search the part number online. Use one with a similar rating. Voltage should be the same since its usually AC line-driven, but make sure.

Sure, you can use a different one. Just make sure you use one with a similar physical size---chances are it'll work.

To be certain though, swap the thermistor AND the degauss coil.

I'm thinking of a thermistor from a 2002 Phillips 19" set that's a similar size... actrally just a hair larger. I'll try that one.

This is a common problem and I just pull one from a junk chassis. This circuit is really not that critical; so, just about any thermistor taken from the degaussing circuit of a junk board should work.

This is a common problem and I just pull one from a junk chassis. This circuit is really not that critical; so, just about any thermistor taken from the degaussing circuit of a junk board should work.

Woo hoo, and I have plenty of junk boards to try!

Its true. I suggested finding one of similar size so that it ill fit better and also put less stress on the existing coil. If you swap the coil too then don't worry.

Let us know how she turns out; the closest set I had to that one was a CTC-130C from 1987. It had stereo with bass/treble/balance, and OSD with 3 AV inputs. No SVideo, unfortunately. Gave that one away after it started scaring me (unusual occurences.)

Are you running the RCA with a cable/converter box or an antenna? I ask because since it has SVideo, you can figure out which unit has the better comb filter, and either pipe composite into the set or use SVideo.

I'm running this set off basic cable, and using the S video to receive video from one of my computers. This particular colortrak model has a *very* good S video picture. Sharper then most TV's. You can actually make out small text... with the resolution at 1024x768!

are ColorTraks the ones that have the incredibly smooth picture?

I had one in a late 80s RCA that did the same thing so I installed one from my junk box-it tripped the breaker. I then tried one from a junker Zenith and it worked fine.

You don't happen to have a CTC159 chassis in your pile, do you? Have a friend who has been looking for some parts off one.

No CTC 159 chassis.

Okay, I put in another thermistor, and turned the TV on. I heard the degaussing noise, then the internal fuse blew! Can the wrong type of thermistor cause the fuse to blow?

Yeah, that was what happened to me. I said the breaker blew but after thinking about it, the fuse in the set blew. You'll have to try another thermistor.

Okay! The colortrak is alive again! Here's a pic!
http://i119.photobucket.com/albums/o121/mrx3750/RCA-2.jpg

I took the thermistor from a 90's Magnavox, as well as a new fuse. This thermistor is encased in a plastic shell, I guess to protect it. Bit of a PITA to fit it in, but lengthening the leads worked.

I've been running the TV for about an hour, and I've powered it on and off a few times during the hour just to be sure.

I also replaced a few caps. They didn't test bad, but they had seen some heat (shrunken wrappers), so I changed em out with some Nichicons that were in better shape.

Also, no Sanyo caps in this set that I've found.

Guess I was thinking of a later chassis regarding the Sanyo;s. Regardless of brand, you did the right thing if they looked crispy. Nice pic, congrats.

I have an RCA CTC185 XL-100 19" table model, bought new in 1999. Great picture on cable. I had only one repair done on this set in all that time; other than that, it's been fantastic, and it is used every day with my VCR and DVD player (I don't watch much else except news and a couple of favorite shows on cable).

As others have mentioned regarding these sets' picture quality, mine makes an excellent picture, comparable to my 1995 Zenith Sentry 2. I also noticed quite a while ago that my set has the inline phosphor CRT and probably inline electron guns as well, which very likely explains why the picture is so very good.

Once the onboard tuner issues were resolved on my set (I'm sure the tech who worked on it to repair the problem I called him for resoldered the ground points around the tuner as well), that was the end of the problems; it's been almost nine years and haven't had anything else done with or to the set, and it still works as well as when it was new. I expect to be using mine well after the digital transition.

The XL 100 line seems to have lower quality CRT's then the Colortrak line. Not surprisingly as Xl-100's are lower end.

I found an 1989 XL-100, almost identical to my 1991 Colortrak. The CRT has a green tint when the color is turned all the way down, and retrace lines are visible. CRT's pretty much shot.

However, the chassis seems to have a lot of interchangable parts with my 1991 Colortrak, so I'll definitely be keeping it.

Wonder if Colortrak and XL CRT's are the same brand... Rebadged mid 90's Zenith CRT's possibly? lol jk

I think by the time this set was made, the XL100 was nothing more than a designation. During the '80's and '90's, the XL100 and ColorTrak chassis were basically the same. The main difference I saw between the two was that the ColorTrak's had a light sensor and the XL100's did not. In my experience, the worst RCA CRT's were from the late '70's and early '80's (found in both XL100's and CT's). In fact, my parents owned a circa '77 19" ColorTrak that used a delta gun CRT and a modular chassis (CTC87, IIRC). The picture tube went bad somewhere around '82 or '83 and my Dad had it replaced. The set was trouble free after that. I've seen a few Thomson CRT's that were bad; but, not that many. The bad ones that I saw were usually in sets with ten zillion hours on them.

Coulda been a ctc-89, radiotvnut. Picked one up from 77 witht he colortrak badge and a weak-weak crt overall. Green was totally dead.

Modular though.

nd yeah, it doesn;t stand for X-tended life, 100% Solid state anymore. After the Thomson sellout its just another name like you say.

Still, they last long and make a nice raster!

Also, During the 80s, the Colortrak sets had the light-sensing photocell which adjusted the brightness in accordance with the room's ambient lighting. Cool feature but got annoying sometimes. My CTC-117A has it. Thats a colortrak from 83 with OSD and remote, bulletproof set.

Also, During the 80s, the Colortrak sets had the light-sensing photocell which adjusted the brightness in accordance with the room's ambient lighting. Cool feature but got annoying sometimes. My CTC-117A has it. Thats a colortrak from 83 with OSD and remote, bulletproof set.

They had that sensor as far back as 1978. It could be annoying at times. Speaking of that damn light sensor, there's one on this 1984 Colortrak I have. Shining my laser pointer at it produces a beautiful picture.

How can I bypass this sensor? Could I just short the leads together?

They had that sensor as far back as 1978. It could be annoying at times. Speaking of that damn light sensor, there's one on this 1984 Colortrak I have. Shining my laser pointer at it produces a beautiful picture.

How can I bypass this sensor? Could I just short the leads together?

That sensor is a light dependant resistor (LDR). I think I would disconnect it from the circuit, connect my ohmmeter to the leads, and then shine the laser pointer at the sensor. Just use a fixed resistor somewhere close to the reading on the meter in place of the LDR. Of course, you could always try it with the LDR disconnected or it's leads shorted to see what picture suits you best.

I think those sensors were big selling points during the late '70's and early '80's. Zenith had their "color sentry" and RCA had their "color trak". At least the feature could be switched off on the Zenith. I had a 27" '91 colortrak that had it. I think they phased those LDR's out soon after that.

The one on my 1984 Colortrak is somewhat recessed into the speaker grille... So my overhead lighting doesn't really hit it!

I want to bypass it so it doesn't tamp down on the brightness. After all, there's a perfectly good brightness knob behind a little panel on the front of the TV.

Magnavox was the first to use this system in the 50s or 60s, with b&w sets IIRC Dont wuote me though..

MRX, I'd try physically relocating the cell or bypassing it.Try shorting it and see how the range on the brightness pot becomes. Like radiotvnut said, experiment with resistor values til satisfied.

Magnavox was the first to use this system in the 50s or 60s, with b&w sets IIRC Dont wuote me though..

MRX, I'd try physically relocating the cell or bypassing it.Try shorting it and see how the range on the brightness pot becomes. Like radiotvnut said, experiment with resistor values til satisfied.

I can't believe I forgot about the Magnavox B&W sets, especially since I used to own one. It was a big TV/radio/phono console from the early '60's (all tube) and it had a light sensor located at the bottom of the left speaker grille. I think Magnavox introduced it again with their "videomatic" solid state color sets from the early '70's.

Magnavox was the first to use this system in the 50s or 60s, with b&w sets IIRC Dont wuote me though..

MRX, I'd try physically relocating the cell or bypassing it.


I removed the cell and twisted the wires together. I ran the Tv for a few minutes, and it has a much better brightness range now. Brightness and contrast knobs work fine.

Is there any danger in leaving this short in place? I'd like to keep it in place, and the TV seems to work fine.