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.

Shouldn't the fuse be a 3.5A, not a 3.2A? All of my RCA lit for the CTC10 shows a 3.5A fuse.

Fuse
 

It is 3.5. Robbed the one out of my 11 that was lower. Now it also has 3.5 as the circuit breaker was bad and pryor owner had put in a fuse holder. Should put in a breaker again like it had.

Original Schematic
 

Also wish I could get the right Lit. I have sams copy and it's ok. Be good to have the right stuff so to speak. If anyone has it I'd buy a copy.

Look on eBay for the RCA field service guides - I have the 1955-1966 one, with all of the early color sets. It also has aa abbreviated parts list for each chassis.

Thanks for the Tip Brian, Found one on Ebay and ordered it. Boy, alot of differences between the CTC10 and 11 Brightness and Chroma Circuits. I see the neon lamps pull to ground and on the 11 a 220K resistor pulls to ground. Also alot of different values of caps and resistors too. So what looks the same isn't. But we've all been there before.

Well Looking for 2 more caps for this beast and I'll have them all done 160 mfd at 250VDC and 50mfd at 450VDC. Then the supply will be done. Anyone have an Idea where to get these? Thanks guys.

Hi Tom,

I think 47 and 150uf are your closest modern values. They should be well within tolerance for supply filters.

Here are some small diameter Nichicon's that are great for re-stuffing original cans. You can search uf and voltage ratings on mousers site and it will bring up several other options.

http://www.mouser.com/Search/Product...47-UCS2E151MHD

http://www.mouser.com/Search/Product...7-UCS2W470MNY9

Hey Thanks Kevin.

found some caps.
 

Well I found a few caps I needed from an old shop here in town. Looks like my CTC10 is going to survive once again. Still lookin for a better CRT for my CTC11 and then I'll refinish the cabinet.

I got a free CTC-10C set in 1975 that had a broken CYP22 kine. I had an FBP22 in my garage that I installed in this set. It works.

Other than a few tubes, the ONLY problem I've seen with my 10 is bad soldering between the chassis ground stakes and the PC boards. The horizontal oscillator board could be tapped with a pencil eraser and the screen image would lose horizontal lock.

I also replaced those neon lamps when one of them broke a lead.

My set has seen no tube replacements since 1979, and is still running just fine on its OEM capacitors.

Don't trust those caps. I tested mine almost 3 years ago with my ESR meter. All checked great. But now that I play it daily they died. Changed them all. You should do the same. Also I found don't trust the meter on your variac. Boy does that make problems you've never seen. Was set at 120 and it was 115. Plays great when you crank it up. Lesson learned

Back to working great
 

After a few weeks of waiting for parts and time to do the job my set is back among the living color. Must admit it turned out great. Thanks for all the input everyone.

It looks great, Tom. I'm sure it feels really good to have your baby back on line :yes:

-Clark