CTC10 Finally a failure
 

Hey guys, Anyone have any common failures in the Horiz Osc circuits? Watching my CTC10 and Freq went way off all the sudden. Have to get more of my equipment home and diag this thing. I tried the OSC 6FQ7 from my CTC11. Same thing. Any help is appreciated.

Is it way off frequency, or is it incomplete scans....? Cap in the yoke...?
Shorted coil in osc. circuit, or cap going bad....

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Is it recapped? If not then the osc. capacitor would be my first suspect. Bad solder joints on the osc. transformer could also be the issue.

That's way off frequency, first thing I'd check is that the osc coil hasn't suddenly shorted or that the hold control didn't open up (check tin whiskers as well).

IIRC, the set still uses a form of Synchroguide circuit. The cap across the coil, .01 mfd @ 600v could be the problem.
The set's old enough to still use some paper caps. :scratch2:

That's similar to earlier nightmare RCA horizontal circuits. Its a
nightmare due to obnoxiously complicated feedback. I had terrible
problems in my CT-100, fixed only by replacing all caps and resistors
in the circuit. All replaced parts tested good, at least at room temp and
zero volts. Check for obvious bad parts. If there are none, try
a full recap and re-resistor with overrated resistors.

I would try grounding the AFC circuit pin 2 of the 6CG7 to make sure its not a defect from the phase detector diodes, then check the .01 across the hold coil and the 390pf of pin 7 would be where I would start.

Had the same CT-100 problem about 6-1/2 years ago. Got tired of troubleshooting, so rebuilt the entire horiz osc circuit. Never did discover exactly what the problem was. It worked fine after the rebuild. Looks pretty with all those new modern parts!

Pete

shorting pin 2 on osc does bring it within limit. No sync of course but the squeal is gone too.. All volts on plates are high when no short. Closer when pin 2 shorted out. Set has been recapped too.

check those diodes out

Well I thought I got every cap. Guess I missed one.. Dammit. I put a terminal strip and left the old caps in place. All unwired of course. Missed 2 sections. 80@ 450 and 160@450. Plus I took out the damm B+ fuse and I really don't know how. Stole the one out of my CTC 11 it was 3 and 2/10 amp. Set played for a short time and it went too. But I didn't unhook old cap's. Just used my sub box. You can tell I've been out of it for a bit. Put cart before the horse. LOL. I'll change caps then try again. I hope all goes ok. I should always check power supplies first. AC can play some good tricks for sure.

My set is up and running but with other slight problems. Now I have no COLOR. Also the 2 neon lamps off of the Brightness control have fallen apart. corrosion on the wires took their toll. I also see they connect to the chroma Bandpass amp. Guess I'll have to wait till my NE 2's come in from Ebay. Couldn't find any locally. Any Idea's if the neons have anything to do with the color?

yes you will have no color without the neon lamps. steve

Those NE2s look like voltage regulators. If so, could you replace with Zeners?

NE2 Lamps
 

Thank you Steve after looking at the circuit I believe your right. Also lowers the brightness too without them. Anyone know where I can get the Thermistor 79 ohms cold. I'm working without it but would feel better with one in there. Don't like to surge that 55 year old transformer. Thanks everyone for the input.