RCA CTC175 no color - Videokarma.org TV - Video

radiotvnut · #1 12-19-2008, 11:30 PM

My ex-TV repairman friend brought me a few more BPC TV's today. Among them was a 20" CTC175. He told me that the CRT was bad. I'm thinking "OK, no problem, I've got an excellent tube that will fit this set". I didn't even bother to plug it in but I checked the tube and the red and blue were very weak.

After changing the tube; I had a color picture minus the green. Some checks revealed that there was no green signal coming out of the jungle IC (LA7810). OK, no problem. I've got a known good IC on a CTC177 that I just parted out (or, it functioned OK in the CTC177).

After changing the IC, I was greeted with an excellent BLACK AND WHITE picture! No color except for the menu. I rechecked my soldering and couldn't find anything wrong. I guess it's time to fire up the scope and see what's going on; but, that will have to wait until tomorrow. I hope I don't have to change that 64 pin jungle IC again! That was not a fun experience!

Before I proceed to fix this no color problem, does anyone have any information that might be useful?

rcaman · #2 12-20-2008, 12:41 PM

those jungle chips are picky. i changed 3 once in a set to get the drives and color back. thet are not fun to change. steve

radiotvnut · #3 12-20-2008, 12:46 PM

If I change it again, I'm putting a socket in "just in case".

andy · #4 12-20-2008, 06:37 PM

000

radiotvnut · #5 12-20-2008, 10:44 PM

I tried that today. I even changed the eeprom with no luck. I'm very close to scrapping this set anyway. My fuse is getting shorter and shorter on these modern sets and I sure don't feel like changing that 64 pin IC again. In fact, I hurled a 27" CTC203 with some sort of weird shutdown problem today. When I pressed the power button, all I got was brief HV and "click click, click click, click click". The B+ checked OK and I disconnected the flyback to see if it would stay on and at least talk, which it did not. After that, I said the heck with it and air mailed it onto the pile. Personally, I liked it before the days of all those shutdown / fault protection circuits. Then, you could actually see a symptom on the screen and/or see smoke and then you knew where to go.

MRX37 · #6 12-21-2008, 11:10 AM

Ah don't junk it yet. You have a new CRT in it. Fix the chassis, and it'll probably run fine until the CRT goes.