View Full Version : CTC40...No color...suggestions?
Tony V 07-19-2005, 06:13 PM Hi Gang,
The RCA Victor CTC40 combo i bought from Bryan last year has developed a problem of no color. It came on all of a sudden as it has been playing like a champ until two days ago. I turned it on and got only a b/w raster. I checked the color killer adjustment and for anything that looks like it overheated on the color board and no go. It produces no color whats so ever...even with station de-tuned and color control all the way up....not as much as a color bar. It has been playing perfect up until i turned it on the day before and had no problems since i got it from Bryan. It has been used as my daily watcher because it played so well. The video is still nice and strong and clear as a crystal, just no color. Ironically i was getting ready to take pics of it playing so Bryan and the rest of you could see it now. This is the combo that created alot of discussion because it still had the Victor and New Vista badges but was totally solid state except for the rectifier. I'm diagnostically challenged when it comes to solid state sets but wanted to pick your brains as far as to what to check out first. I know several of you have worked on and are very familiar with this particular chassis and would appreciate your input. I do have a schematic for it. Another question...if it turns out that it needs one of the transistors or the crystal on the color board....are these or a suitable replacement still available? This has always been a fear of mine when buying a vintage solid state set. That is why all of my tv collection (except for this RCA and my Sony's) are tube sets.
Thanks,
Tony
rca2000 07-19-2005, 06:23 PM I have at least 2 ctc-40 chassis, and a complete set, and know where another one is. I could sell you a color board, or a WHOLE CHASSIS, if you want it, most likely.
old_tv_nut 07-20-2005, 10:56 AM Not familiar with this chassis, but if it is discrete transistors and not ICs, almost any general purpose small silicon transistor (just careful whether it's NPN or PNP) should work anywhere in the low-level chroma circuits. So, a board replacement would be quickest, but if you do that, it still would be worthwhile to repair the dead one and have a backup.
bgadow 07-20-2005, 10:57 AM I'm a dunce on solid state. Maybe a cap somewhere??? I should mention that I have a stash of NOS transistors & ICs which I have inventoried so if someone has a need, post it. Somebody is bound to have it, right?
old_tv_nut 07-20-2005, 11:06 AM Before I could make the haziest guess, would want to see the schematic and know how old it is. If you have the schematic with voltmeter readings, the quickest thing to do first is check DC levels - troubleshooting isn't much different for transistors or tubes when you're starting from step zero, just different voltages expected and maybe different things commonly fail if you have the experience to know that chassis's foibles beforehand. As I said, I have no particular familiarity with this chassis, so would just have to go on general principles. If someone else on the forum has has seen this before, their suggestions would be much more valuable.
Chad Hauris 07-20-2005, 11:23 AM Try turning the color control up and down with the fine tuning turned off station like you had done...does the hue of the picture change at all (like from black and white to a purplish hue)...if you get some color change this means that the chroma signal channel is working but the 3.58 mhz oscillator is not.
If there is absolutely no change in color there is a break in the chroma signal path.
This is a discrete transistor chassis which is kind of laid out like the CTC-39, it consists of transistors soldered directly to the circuit boards, no modules.
I have not worked on ctc-40 personally---have done research on it though: I think it would be pretty difficult to change out a whole board as they are soldered to the chassis and have a lot of connections.
We use a B&K transistor tester which identifies leads of transistors and good/bad quality...it has made the difference between successful repair of transistor equipment without even needing a schematic or real difficult troubleshooting and not being able to fix the item. I would highly recommend an in circuit trans. tester such as this...ours has never been wrong.
Tony V 07-20-2005, 11:56 PM Chad,
The same thought had crossed my mind when i turned the color control all the way up and detuned the channel when i saw no change. It keeps a b/w raster with no hue change so i guess the chroma path is broken. I'll pull the chassis out in the next few days and check everything more closely as i want to get it going again as its has been a good performer for me. I might ad also that this sucker has the best FM tuner i have ever owned in it. Most FM tuners i have or have had only pick up about 8 to 11 stations. This one picks up roughly 30 stations and with using only on its built in antenna. Thanks for the heads up on the B&K as i'll start hunting for one of those as it looks like i'm going to be needing it.
RCA2000 and Bryan,
I might be hitting you guys up on some parts once i get this figured out and appreciate your offers.
I'll keep you guys posted on what i find and am appreciating everyones input. I guess its about time for me so do some dabbling in solid state as i been putting it off for a long time. I understand the theory but havent had much hands on experience with it.
Thanks,
Tony
polaraman 07-22-2005, 12:24 AM Tony V,
There is a factory repair book for the CTC 40 on ebay. Here is the link.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=6195547182&category=3638&rd=1
polaraman
TVtommy 07-22-2005, 04:56 AM CTC-40, RCA's first solid state. Bear of a chassis. SCR deflection, single ended vertical output. These are the two areas where i have found semiconductor specs. to be critical.You can change the whole board with the color subsection on it if you are glutton for solder and punishment. I have one that was mint except for a bad flyback until the flood of '99 ruined my stored collection. I still have the rusted chassis and a ctc-41 Chassis that is the same except for flyback\Quadrupler in Hv.sect. You really need a good schematic for it. You need to look for cold solder joints, especially on the wire wrap pins. Could just try changing the xtal, i think the one from a tuber like a -38 or -39 will work
Chad Hauris 07-22-2005, 09:27 AM Tv Tommy thanks for your input...I agree, check the wire wrap pins especially where power enters the circuit board...the connections are probably very similar to those in the tube sets...have seen bad solder joints at these kind of pins in a ctc-16 and ctc-38. Check that you actually have proper DC voltage at the transistors...I should be able to scan the field service guide schematic for ctc-40 in the next couple of days if you need it.
TVtommy 07-27-2005, 06:47 PM Ya know, this whole CTC-40 thing has really opened up a sentimental (actually more mental than sentiant) can of worms for me. Since the disaster struck that dang thing keeps popping into my mind more and more often. It was the impetus 20 years ago that made me buy a used copy of a solid state tv service book by Jack Darr. That pub. coverered the first 4 solid state tv's of merit, the RCA CTC-40, Motorola ts915/919, sony kv 1310 and a Hitachi whose model number excapes me except for the fact that it had two 3.58mhz oscillators for some odd reason because of an oddball color killer scheme. Anyway, that book talked about the RCA CT-100, CBS 205c1 and that 19" Motorola from 1955, 3 sets that I had no idea that even existed up until that time. I since owned all but the Motorola, but it ain't over till the fat flyback sings! Now I Digress. I reckon the whole point is if there is anyone in reasonable distance from southside VA that has one of these cluttering up their space, let me now (does this belong in the classifieds?) It can definitely be in questionable condition, Tv only does not matter, useable cabinet prefered, can be CTC-41 (I really need to start getting out more)!
vintagecollect 08-12-2005, 04:05 AM ...
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