Hello,

Last night I dragged home a CM roundie. Theres not a lot to go on with it. Most the tubes are CM branded with date codes of XX-65. Has a RCA Hi lite 21FBP22A crt in it. Theres a chassis # of C20-1j i think it is. I will try to upload photos here. I may have to resize them. Maybe a CTC-15 clone?

Photos

Front. A bunch of the controls like tone are sorta hidden under the bottom 3 controls

It's definitely a RCA clone. The type Horizontal, damper and vertical output tube will determine whether its a CTC12, 15, or 16 chassis clone. I'm leaning towards it being a CTC15.

Tony the damper is a 6dw4. Hor and vertical are 6fq7 and 6gf7. 1av2 focus rect. Should I try to get the sams for a ctc 15/etc or for this set specifically?

Also the diode bridge is mounted on terminal strips under the chassis, not on the pcb.

I downloaded the sams for rca ctc 15 off the early television museum. Looks really similar except the CM uses a tube focus rect and the rca ctc 15 uses a diode.

Tony the damper is a 6dw4. Hor and vertical are 6fq7 and 6gf7. 1av2 focus rect. Should I try to get the sams for a ctc 15/etc or for this set specifically?

Also the diode bridge is mounted on terminal strips under the chassis, not on the pcb.

I downloaded the sams for rca ctc 15 off the early television museum. Looks really similar except the CM uses a tube focus rect and the rca ctc 15 uses a diode.

Tony the damper is a 6dw4. Hor and vertical are 6fq7 and 6gf7. 1av2 focus rect. Should I try to get the sams for a ctc 15/etc or for this set specifically?

Also the diode bridge is mounted on terminal strips under the chassis, not on the pcb.

I downloaded the sams for rca ctc 15 off the early television museum. Looks really similar except the CM uses a tube focus rect and the rca ctc 15 uses a diode.

Zenith nut, You are correct about the diode in the RCA. Here is the RCA CTC-16 tube listing which is similar to your CM model.

Zenith nut, You are correct about the diode in the RCA. Here is the RCA CTC-16 tube listing which is similar to your CM model.

I think I have a lead on the sams for this CM. Sams 831-2 but im not gonna fork up $22 bucks until I know thats what is.

Zenith nut, This page on CM CTC-15 clones may also be of interest to you:

Zenith nut, This page on CM CTC-15 clones may also be of interest to you:

Thats it. A CMC 20. Sams 831-2. Thanks!

Zenith nut, This page on CM CTC-15 clones may also be of interest to you:

Steve, the hor osc coil broke. Can the little red wire be soldered together and repaired? It broke at the base. The core is intact. I have a soldering station with a thermostat for the iron.

I think I have a lead on the sams for this CM. Sams 831-2 but im not gonna fork up $22 bucks until I know thats what is.

Zenith nut, Not to overstay my welcome, but here is the tube layout for the CM CMC-20 chassis.

Zenith nut, Not to overstay my welcome, but here is the tube layout for the CM CMC-20 chassis.

No stay as much as you can! Just looked at whats left of the tube chart on the hv cage and it calls for a 1v2 focus rectifier not a 2av2 listed in the cmc20

Rca ctc 16 uses a 1v2

No stay as much as you can! Just looked at whats left of the tube chart on the hv cage and it calls for a 1v2 focus rectifier not a 2av2 listed in the cmc20

Rca ctc 16 uses a 1v2

I noticed the CTC-16 as I posted. And the different focus tubes as well. Perhaps a production change on the layout chart. The tube complement list also has the 2av2 listed. Checked my RCA reference book and the 1V2 & the 2av2 are not listed as interchangeable. I have no experience w/these "later" model roundies. I would suggest that you repost or re-ask your questions to VK. Plenty of folks w/CTC-15's and if you're lucky a CM clone.

Best in the new year,

-Steve D.

I noticed the CTC-16 as I posted. And the different focus tubes as well. Perhaps a production change on the layout chart. The tube complement list also has the 2av2 listed. Checked my RCA reference book and the 1V2 & the 2av2 are not listed as interchangeable. I have no experience w/these "later" model roundies. I would suggest that you repost or re-ask your questions to VK. Plenty of folks w/CTC-15's and if you're lucky a CM clone.


Best in the new year,

-Steve D.

Where in videokarma should I repost this?

Where in videokarma should I repost this?

Hey Alex, I just now returned to my computer. I suggested VK color tv section as you did before. However, you did fine logging on to The Vintage TV Collectors site as well. I read your inquiry about the blue lateral magnet. You received the proper response. Hopefully you'll find the original or a good replacement. I also hope you received a reply on the hor osc coil. I'll look forward to viewing your progress on the CM.

Best,

Steve Dichter
[email protected]

I noticed the CTC-16 as I posted. And the different focus tubes as well. Perhaps a production change on the layout chart. The tube complement list also has the 2av2 listed. Checked my RCA reference book and the 1V2 & the 2av2 are not listed as interchangeable. I have no experience w/these "later" model roundies. I would suggest that you repost or re-ask your questions to VK. Plenty of folks w/CTC-15's and if you're lucky a CM clone.

Best in the new year,

-Steve D.
The set appears to be a cross between a CTC16E and a CTC16X. All the 15 clones used a voltage doubler.
The 16E used a 1V2 where the 16X used a 2AV2.

The set appears to be a cross between a CTC16E and a CTC16X. All the 15 clones used a voltage doubler.
The 16E used a 1V2 where the 16X used a 2AV2.

The funny thing is, is that this set DOESNT use a tube focus rectifier. But it lists one on the tube layout. Theres a mount cut out in the hv cage for one too.

Hey Alex, I just now returned to my computer. I suggested VK color tv section as you did before. However, you did fine logging on to The Vintage TV Collectors site as well. I read your inquiry about the blue lateral magnet. You received the proper response. Hopefully you'll find the original or a good replacement. I also hope you received a reply on the hor osc coil. I'll look forward to viewing your progress on the CM.

Best,

Steve Dichter
[email protected]

Thanks Steve.

I have a friend who has a Curtis Mathes roundie combo unit that chassis was pretty much designed right after the RCA CTC 16s

I always had to laugh at some of the clone sets like CM and Sears. On that set the picture tube bezel is plastic vs metal on the name brands. I'd always heard that Sears did that on lots of stuff they sold.

I have a couple of Curtis Mathes C-20 sets. You will find the chassis has characteristics of both the CTC-15 AND CTC-16.

If it has auto-degauss, that would make it closer to a '16.

I have a couple of Curtis Mathes C-20 sets. You will find the chassis has characteristics of both the CTC-15 AND CTC-16.

The last CM roundie was a knockoff of the cheapie RCA CTC20. 6GH8's galore.
Slight difference, it used the lousy 6KM6 horiz out.