RCA CRT TV - Chassis CTC169CF - Page 2 - Videokarma.org TV - Video

radiotvnut · #16 03-09-2009, 11:36 AM

That disc under the big resistor is the degaussing thermistor. They are bad about falling apart from heat. If it's still intact, it should be OK. Oh, and don't pay $19 for that transistor just yet. I think we can find it much cheaper with a little looking.

radiotvnut · #17 03-09-2009, 11:45 AM

SGIF transistor - $9.29
IC - $5.09

www.mcmelectronics.com. Just key in the generic numbers as the price is cheaper than the RCA part numbers. MCM should also have the electrolytic caps in generic form. I think MAT electronics still has the whole kit for something like $9.99; but, I'd be a little afraid of it. Some of those parts in those cheap repair kits are second rate and may come back to haunt you. I had that happen with a newer Philips set. The horizontal output transistor that was with the kit shorted after 10 minutes of operation. I replaced it with another part and I guess it's still going somewhere.

Jeffhs · #18 03-09-2009, 12:02 PM

Quote:

Originally Posted by radiotvnut

Those diodes are probably good. If you are using a digital meter, check them on the diode scale. The likely problem is the chopper transistor (mounted on a heatsink) in the power supply. This transistor likely took out the control IC. In addition, replace the electrolytics in the switching circuit. 39uf, 2.2uf, 15uf, and 470uf. They are all located right there around the IC and transistor. And, check the horizontal output transistor for shorts. It's on a big heatsink close to the flyback transformer.

BTW, don't use NTE, ECG, or any Chinese knock-off parts in this application because they likely will not hold up. Use original RCA parts if possible. www.tritronicsinc.com should have the parts.

IMHO, the CTC169 was the best Thomson era RCA chassis made.

The CTC185xx series isn't half bad either. Once the grounds around the tuner (a major problem with this series, and all CTC-17x-18x series chassis until the CTC203, because of the onboard tuner) are soldered properly, this chassis will run trouble-free for years. Mine has nine years on it and still works as well as when it was new;

I had the grounds all resoldered about eight years ago, the last time I had the set serviced. Not a bit of trouble with it since then, and a beautiful picture with the original CRT.

Brian1234 · #19 03-12-2009, 11:43 PM

Here's what I have now, as found at mcmelectronics.com:

Transistor: 200165 $17.13 (SGSIF461 $9.29)
IC: 200419 $13.67 (TEA2261 $5.09)
47uf @ 50v: 31-5825 $1.60
2.2uf @ 100v: 31-7515 $0.61
15uf @ 50v: 31-5800 $1.26
470uf @ 35v: 31-5705 $2.08
1N4007: 1N4007F $0.40 Package: DO-41 (price for 10)

I'm tending toward the RCA transistor and the TEA IC. Good choice?
Do those look like proper caps? (especially voltages? all polarized?)
Did I pick the wrong diodes (DO-41 is glass?)

I have no specs on the thermistor, pointers please.
I stopped in at a TV shop and he said he replaces the zener too... would that be CR122 @ 3V? What wattage?

Sorry to be such a pain... unfortunately the only local parts shop left is all NTE so I'm left to pick from online store descriptions... I find them confusing. Just one example: the MCM page for the 200165 has a photo of the SGSIF461.

THANKS!

radiotvnut · #20 03-13-2009, 12:29 AM

That list looks correct. You can use the original RCA transistor/IC or the SGSI/TEA parts which are cheaper. As long as they are not some Chinese knock-off parts, you should be OK. I don't know about the Zener diode as I"ve never had to change one; but, I've not worked on near as many as the TV shops have. Most of the ones I've worked on were either TV shop rejects or ones given to me by individuals. The 1N4007's should work fine in the power supply. I usually order those by the 100 as they are a common failure.

radiotvnut · #21 03-13-2009, 12:36 AM

Thermistor P/N = 207768. MCM has it for about $8.

MRX37 · #22 03-13-2009, 01:12 AM

Just going off my experience: thermistors from Zenith chassis seem to work fine in RCA chassis, and they have a plastic casing around them, probably to help prevent fall apart. Might need to lengthen the leads to make one fit though.

Brian1234 · #23 04-02-2009, 08:50 PM

Hey, I think I just found an identical TV on craigslist nearby, the ad says:

"Tv is working, but has slight red tint to pictire." ($30)

[Edit: Darn it, I had a question here about the rear panel adjustments but I probably should have grabbed it asap, it's been sold]

radiotvnut · #24 04-02-2009, 11:02 PM

It could be a simple adjustment or the CRT could be weak. Look at it before you buy. If the picture is bright, sharp, and not too red; it probably needs adjusting. If the picture is blurry, dim, "bleeds" on high brightness scenes, or any combination of the above; the CRT is probably on it's way out and I'd leave it alone. I've learned over the years that when someone says "slight red tint", you can take it with a grain of salt. Many times, red is the only color that's working.

Brian1234 · #25 04-02-2009, 11:18 PM

Looks like I was editing my last post while you were typing. It's been sold... I probably would've liked that unit.

Thanks for your feedback again

Brian1234 · #26 04-11-2009, 11:17 PM

OK, I received my parts! Not exactly as listed previously, I sorted through the capacitor choices more. I went with the SGSIF transistor and TEA chip.

I'm concerned about the diodes I ordered though:
http://www.mcmelectronics.com/produc...N4007-/1N4007F
These are 1000V 1A. However, they are (physically) about half the size of the originals. Going by gut feel, they look too little to power the whole set. The numbers on the originals are "115 A23 925 -2" and while I get google results for A23925 I'm not finding specs. :^(

radiotvnut · #27 04-11-2009, 11:23 PM

The 1N4007's should work fine. For some reason, RCA liked to use those large diodes. The worst that can happen is they'll short and blow the fuse; but, I don't think you have anything to worry about.

Brian1234 · #28 04-19-2009, 08:48 PM

I finally put in all the parts, but guess what I noticed when I took the old ones out... the chopper was an SGSIF and the chip a TEA... it's been repaired before. Of the 4 caps I replaced, it looked like 3 were still original and only one had been replaced.

With that in mind are there any other parts I should check before I put the chassis back in?

radiotvnut · #29 04-19-2009, 10:53 PM

Pretty safe bet you can fire it up now. Just make sure that you installed the parts correctly and you didn't splash solder anywhere.

Brian1234 · #30 04-20-2009, 11:25 PM

IT'S ALIVE !!!!!!!!!!!!!!!!!!!!!!!!!!

Thanks to everyone, especially radiotvnut!!

I've had it on for a few hours now and am going to run it a few days before returning it to my sis.

First I tested via the tuner, now have it going via NTSC/audio on Input 1 but I have to go to channel 91 to see that? Going down from channel 2 it goes through 99 then 98 then to 'Input 1 91' which seems like an odd place for it. I think we'll end up plugged in via S-Video but the back panel doesn't say if that's input 1, input 2 or something else. Know where I can find a user's manual online?