CTC-9 restauration. - Videokarma.org TV - Video

avalon1308 · #1 01-03-2007, 02:55 AM

I am sure lots of you will know the answer. I am restauring a CTC-9. It had a dead FJP in it and I replaced it with an original CYP. The set if fully recap'd and a 63Kohm resistor was added for the second anode(did not have a 56K). When I turned on the set, I had a picture for 2-3 minutes then I guess there was a flash with a little "FRRRT" in the back. Since then, nothing, no picture. Checked everything. All voltages on the neck of the CRT are present and correct, they vary nicely with all controls. The HV is very near 20,000 volts.
The schematics says it should be between 19kv and 21kv(varies from one schematic to another).
This is the first time I play with a CYP. Firstly,I am not sure which one is the second anode. Is it the one in the red area (on top of the first anode connection). Only one think I realized is that the HV varies a lot with the
hor sync control and I don't know if this is normal behavior. Could an inverted connection of the anodes kill the tube.
Thanks a lot for any help.

snogcel · #2 01-19-2007, 02:24 PM

You might take a look at the focus voltage, if you haven't already. This should be approximately 5KV, found on a thick lead going to the CRT socket. That's enough voltage fart and flash, and the loss of this voltage can black out the raster. It is developed in the flyback section, and if I recall correctly you'll find a 1V2 focus rectifier tube involved in the circuitry.
Just a thought - Good Luck!

andy · #3 01-19-2007, 02:47 PM

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avalon1308 · #4 01-20-2007, 05:59 AM

Thanks for your tips,
you're probably right, it could come from the focus part. I would have never thought of checking that voltage for no raster. The weirdest thing is happening. With the HV cage in place it does not work, with the HV box removed all is fine!!. I checked for shorts and bad contact and nothing to be found. Could let it go without the cage but not really safe. I guess it was good to remove the cage because I found out that the Flyback is running very hot and the wax is melting. The efficiency coil is seized up and I cannot turn it (if this could solve the temp problem). I am affraid to break it by forcing it to move. Is there a way of freeing the ferrite. About the 56K resistor, I replaced it with one with the proper value, this can help as well. Again, thanks for your help.

Phil Nelson · #5 01-24-2007, 02:20 PM

Quote:

Originally Posted by avalon1308

With the HV cage in place it does not work, with the HV box removed all is fine!!.

Perhaps this is a dumb comment, but if the problem magically disappears when you remove the HV cage, doesn't that suggest there's something shorting (or leaking?) to the cage? What else could be the cause?

Phil

avalon1308 · #6 01-24-2007, 02:49 PM

Absolutely right of course, but so far, I have not found the short or leakage. Probably an arc towards the cage. One thing is for sure, the HV is correct even with the cage installed but no raster. That is why I am focusing on the focus voltage now(thank to some AK members). My first priority is to find a way to reduce the temperature of the flyback. The HO cathode current is 210 mA and the regulator current is less than 1mA. I thought that although on the high side these currents were OK for the flyback. A CTC9 flyback if I fry it will be very hard to find if not impossible from this side of the pond. From 10 on they are still available but 9, so far no luck.Thanks

bgadow · #7 01-25-2007, 12:23 PM

Could one of the screws holding the cage to the chassis be causing the short? Might be too long and touching a component under the chassis.

avalon1308 · #8 01-30-2007, 03:27 AM

The screws are not the original ones and yes they might be too long. Will insert them one by one and find out. That set does not have any original screws even for the back panel. Seems it has been put together from a few different sets. Just received the new linearity coil, hope this will help the temperature problem.

Phil Nelson · #9 01-30-2007, 12:41 PM

I wonder what would happen if you temporarily line the cage with electrical tape and put it back on. Might help narrow down what is happening.

Just thinkin' out loud . . . .

Phil Nelson

avalon1308 · #10 02-03-2007, 03:25 PM

Having followed the advice, I put the cage back on the set without the screws and working fine. It started acting up after the second srew was put back in place. Only by moving the cage slightly, the focus started acting up and the screen would go out of focus. The culprit is now replaced and the set is OK. The old focus cable looks perfectly fine. I guess it became porous over the years. The eff coil was replaced and the current is now 190 mA. It takes 2-3 minutes for the color to sync when powered up with 110v. All tubes checked OK. When the set is poweredup with 120, the color appears immediately. could live with it that way if it does not degrade any further.
Thanks for all your tips.

roundscreen · #11 02-12-2007, 07:18 PM

Quote:

Originally Posted by avalon1308

Having followed the advice, I put the cage back on the set without the screws and working fine. It started acting up after the second srew was put back in place. Only by moving the cage slightly, the focus started acting up and the screen would go out of focus. The culprit is now replaced and the set is OK. The old focus cable looks perfectly fine. I guess it became porous over the years. The eff coil was replaced and the current is now 190 mA. It takes 2-3 minutes for the color to sync when powered up with 110v. All tubes checked OK. When the set is poweredup with 120, the color appears immediately. could live with it that way if it does not degrade any further.
Thanks for all your tips.

You did a really nice job on your set. awesome color.

Phil Nelson · #12 02-12-2007, 09:52 PM

Just for the record, I'd like to compliment bgadow's detective work in finding the too-long replacement cage screw at long distance.

That's the kind of real-life tip that you can't learn from a book -- and why forums such as this are invaluable for folks (like me) who don't have mentors peeking over their shoulders.

Phil

jpdylon · #13 02-03-2007, 03:34 PM

Looks Great!

Glad you were able to solve the problem. What movie did you take that screenshot with?

old_tv_nut · #14 02-03-2007, 03:39 PM

For the color problem at 110 V, I would try turning the Horiz hold back and forth in case it's a H phasing (burst gate) problem instead of something needing alignment in the color oscillator.

avalon1308 · #15 02-03-2007, 04:00 PM

The screenshot is from "Meet me in St Louis" the Trolley song. Very bright color movie. Wonderful on old color set.

I did try the H hold back and forth but did not help. When the set is cold, I have wide horizontal color lines (3-4 on full screen). When sync'd, the tint although I can get the right flesh tone is only effective on 1/2 of the potentiometer course. A slight touch (1/4 of a turn) of the A17/18 coils did help a little but still very touchy.