CTC-4 Director 21 - Page 3 - Videokarma.org TV - Video

andy · #1 07-21-2016, 10:00 AM

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Electronic M · #2 07-21-2016, 02:45 PM

Quote:

Originally Posted by andy

Some things I've run into are accidental shorts in a tightly packed point to point chassis like this, or breaking one the the fine wires on a coil or transformer when it connects to the terminal.

CTC-4s have PCB IF, sound, and parts of other stages.

SwizzyMan · #3 07-21-2016, 04:44 PM

changed the channel to 4 and subbed the 3rd IF tube. Not much difference, but now I can get a pretty clear b&w picture, but when I turn on the color all the interference shows up. Once I get rid of all color the interference goes away. The fine tuning knob still has only an eighth of a turn before I lose sync, but about half way through the 1/8 turn clockwise the color starts to fade but does not disappear and the overmodulation hum gets louder.

SwizzyMan · #4 07-21-2016, 05:13 PM

I must also note that none of the tubes are shielded. I'm sure that isnt helping my interference problem anyways. And Dave, according to the previous owners the set hasn't been powered up since last December.

Electronic M · #5 07-21-2016, 06:44 PM

Quote:

Originally Posted by SwizzyMan

I must also note that none of the tubes are shielded. I'm sure that isnt helping my interference problem anyways. And Dave, according to the previous owners the set hasn't been powered up since last December.

The IF tubes and a few others are supposed to have shields....I recommend finding some shields before messing with it too much.

andy · #6 07-21-2016, 05:52 PM

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old_tv_nut · #7 07-21-2016, 10:07 AM

Sometimes it is possible for the fine tuning to be so far off that the tuner is recieving while set on the next channel and/or tuned to the wrong sideband of a simple modulator.
If you are using channel 3 on the TV, try channel 4 or vice versa. If your modulator is versatile, try both one channel up and one channel down.

DaveWM · #8 07-21-2016, 10:12 AM

baluns, terminations, OTA on that channel, connections, etc...
I had one with an intermittent balun in the tuner that gave me issues once.

old_coot88 · #9 07-21-2016, 11:11 AM

Just for the heck of it, try subbing the last IF tube. Ringing/smearing in the luma is a not-uncommon problem caused by the last IF tube, even tho the tube tests 'good' on a tester.

SwizzyMan · #10 07-21-2016, 12:43 PM

I'll switch to channel 4 and sub the 3rd IF 6AN8. Don't see why 8 months would totally mess this thing up.

DaveWM · #11 07-21-2016, 02:10 PM

was nothing done to it in those 8 months?

jstout66 · #12 07-22-2016, 05:42 AM

It has to be something simple, since it worked 8 months ago. I'd agree with what Andy and Electronic M said.... Put the shields back. Also, I wouldn't attempt an alignment. They NEVER go out of alignment on their own, unless it's a component failure or someone in the past has been screwing around, and 9 times out of 10, it was somebody that got happy with a set of Radio Shack "diddle sticks". I was also reading some earlier posts. I wouldn't worry too much about the caps. If it was a repair tech that had it in the past, I'd assume it's been re-capped. Maybe I missed it in a prior post, but have you looked yet to verify? I also wouldn't worry too much about the tube conversion job. It looks like it was done long ago, and if it wasn't done right, those problems would have surfaced eons ago. It will be something so simple, you'll probably smack yourself on the head when you figure it out.

DavGoodlin · #13 07-22-2016, 07:48 AM

What generator setup would you be using for an alignment?

I have two very original and crispy CTC16 chassis' I must repair for a combo owner, so I will be looking at this issue for sure.

Usually the adjacent sound reject adjustment (before the first IF) and sound reject (at the third IF stages need to be dialed in first.
Not sure of a CTC4 swizzy, but start there - it could be all you need to tweak.

miniman82 · #14 07-22-2016, 11:19 AM

I can do alignments Dave, I have a full setup here and I'm only a state away from you. Just did a CTC-9 not long ago.

Phil Nelson · #15 07-22-2016, 02:40 PM

I'm not clear on the restoration status of this set. Did the previous owner do some minimal "make it work" repair years ago? Did he do a full restoration? Something in between?

If the original electrolytics have not been replaced -- or at least checked! -- I would not feel safe running this set for prolonged periods.

Forget alignment for the moment. TVs don't un-align themselves by sitting around. Install a full set of tube shields and see if they help.

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html