2 RCA tube color sets & other stuff found.

[radiotvnut]

I went to see an older man today that used to own a TV shop years ago and he loaded me up with some stuff: An RCA Victor combo with a CTC25 chassis, a metal cabinet CTC38 set, a '78 19" Sony, a '70's 19" GTE Philco B&W, and an old B&W console of unknown make.

He said he thought the combo needed a flyback and the metal one had color problems. The chassis is loose in the combo and it's very dirty (well, they all are). No way I'm plugging these in until I do some basic checks. I know I'm junking that B&W console if anyone needs anything out of it.

That combo feels like it weighs about 4000 lbs. I do have the back. I just took it off for the picture.

[freakaftr8]

Sweet finds!! Im envious of that combo unit!!

[drh4683]

Nice finds. Does that combo have the 6AQ5 audio output? The early production ctc25's had the solid state audio out mounted on a large heat sink. I cant tell, but yours looks like the tube version. supposedly there were problems with reliablity while those chassis were in production and they reverted back to the 6AQ5. I have a late production ctc25 set from mid '66. Its a interesting chassis and it does not get brought up alot on the forums. Most of the time you will find a ctc-16 roundie or a ctc-31 or 38 rectangular set.

I always liked those ctc38 table sets with the tilt out control bin.

[radiotvnut]

Bad news. The CTC38 has a bad flyback. I powered it up and the HOT runs hot and the flyback has a burnt smell as well as old wax drippings. I just left it on long enough to see what would happen. At first, the CRT checked almost dead. About 10 minutes cooking on 8 volts solved that. When I change the fly, I know I'll need to check for a proper horizontal drive signal and monitor the HOT cathode current. Is there anything else I should do to prevent possible problems? I don't know when I'll get around to fixing it. I need to fix what I've already got torn apart. But, I'm sure it's worth messing with since metal table model color tube sets seem to be rare. I didn't find that many back in the '90's when tube sets were still common.

The Sony somewhat plays. I'm sure some cleaning and adjustment will help. The GTE Philco B&W plays but the CRT is weak and it has vertical sweep issues.

Oh yes, I was going through the record compartment in the combo and found the original instruction book. The instructions on the Sony were also there. I think mine has the tube output; but, I'll double check to make sure.

[Findm-Keepm]

Originally Posted by radiotvnut

Bad news. The CTC38 has a bad flyback. I powered it up and the HOT runs hot and the flyback has a burnt smell as well as old wax drippings. I just left it on long enough to see what would happen. At first, the CRT checked almost dead. About 10 minutes cooking on 8 volts solved that. When I change the fly, I know I'll need to check for a proper horizontal drive signal and monitor the HOT cathode current. Is there anything else I should do to prevent possible problems? I don't know when I'll get around to fixing it. I need to fix what I've already got torn apart. But, I'm sure it's worth messing with since metal table model color tube sets seem to be rare. I didn't find that many back in the '90's when tube sets were still common.

Two things - you're now looking for a Thordarson FLY-312 or RCA part number 119834 IIRC. There's a 119834 on eBay right now (no, not me, and I don't know/can't vouch for the seller). When you do install the new flyback, crank that efficiency coil for the proper (low) cathode current. A 0-250 mA meter (I use an analog one, bypassed with a .22uF cap) with clip leads works fine. When you finish, put a pigtail 500 mA fuse in the cathode circuit. It'll blow before the new fly cooks.

Cheers,

[Chad Hauris]

I wonder if the flyback is completely bad in this case or just has been overloaded but still has a chance...On a CTC-16 and CTC-38 both had power supply or bad solder joint problems which caused no voltage to the horizontal oscillator. This overloaded and destroyed the 6JE6 tubes but repairing the oscillator power supply and replacing the output tube brought back proper operation.

If possible though a new flyback is the best solution along with a cathode fuse and current adjustment...have had a flyback fire in a CTC-31 which completely destroyed the flyback and HV tube socket. Don't know if this was an arcing problem, just bad flyback or output tube overload. The portable sets had either a circuit breaker in the horiz output cathode, a thermal fuse on the HO tube or both but for some reason the consoles/metal table top models never had this protection.

The easiest check for oscillator operation is to measure the negative grid voltage on the horizontal output tube. No voltage or weak voltage indicates poor or no oscillator operation.

Also I have had problems in the 6BK4 circuits cause problems in Magnavox sets where the flyback was overheating.

I have put in a fuse clip in the horizontal output cathode circuit and first put in a 6 volt fuse lamp to set the efficiency coil (minimum brightness on the lamp) then replaced the lamp with a 300 ma fuse.

[radiotvnut]

Thanks for the information. Now, I've got something to go on when I get back on this set. I'm going to check with the local parts house and see if they by chance have a fly stuck back somewhere.

[andy]

Can you post bigger pictures? Your pictures are always too small to see any detail. They can be as big as 900x900.

[radiotvnut]

Here are some more pictures of the CTC25 combo.

[radiotvnut]

Pictures of the CTC38. This set is really nasty inside!

[radiotvnut]

And here is the Sony KV1911 "econoquick" set from '78. Were these decent sets? I sure hope it's not the one with the SG-whatever horizontal output.

[radiotvnut]

Well, I fired up the combo and the stereo is completely dead and the TV only has it's dial lit. I found a receipt where the CRT was changed in '78. The tube checked almost dead with an H-K short on the red gun. Cooking it didn't do much good. The rejuvenate function brought the red up to about 60% and the blue and green to about 75% and also cleared the short. The label on the CRT is chewed and faded; so, I don't know who made it. There is no maker listed on the reciept. I did double check and the set does use a 6AQ5 output tube. I think a mouse made his home in this thing. Sitting these sets in a less than perfect environment didn't do them any good! I'd rather remove a set from some little old lady's living room than out an old, unheated, damp building.

[andy]

The stereo in that combo looks a lot like the front panel of this RCA table radio.

That CTC-38 looks like it could clean up ok. Any table top RCA color set is a rare fine these days.

I see the Sony is developing a green halo. I guess it was just a matter of time. Those were good sets, but tended to have weak red and blue guns. Even 20 years ago, every late 70's Sony I got had a green picture.

[Chad Hauris]

Weren't the Sony Trinitrons some of the last sets to use the bonded CRT faceplace (accounting for the green halo?)
I'd check the circuit breaker and degaussing thermistor on the CTC-25...have seen both of these open and cause no B+ (they are both in the input to the rectifier) Also check for bad diodes/caps in power supply.

[colorfixer]

I was wondering about the halo on the Sony as well.

I have the same set and had to change the tube from another dead SG powered set.

The original did not have a bonded face (I popped the original tube, and it definitely didn't have a bonded face ).

I have a 76 vintage 12" Sony monitor/receiver which was a "hangar queen" from a transmitter site with almost no hours on it, but the raster was very green. What makes them do this? I re-did the gray scale tracking and it must have at least another 15 years of daily use on my workbench without re-occurrence.