Need TM-21 monitor manual
 

Howdy all,

Does anybody happen to have a service manual with schematic for the RCA TM-21 monitor?

I've struck a deal to purchase one, and would like to get a head start on the capacitor order.

I've always wanted a 21-CT-55, in order to get the larger, easier to watch 21 inch screen with wideband I/Q color (the 21-CT-55 is R-Y/Q, but I think it's a simple mod to switch it over to I/Q). Anyway, they keep eluding me, and the opportunity to buy the monitor came up; it has a 21 inch jug with wideband I/Q chroma demod. I figure it's the closest I'll ever get to a CTC-2B...

Your memory sucks, you know that?

I’m scanning mine this weekend, hold your horses. Lol

Hey Nick, mind posting that publicly (maybe through the ETF)?

Based on tube compliment and things I've read of the TM-21 I'd really like to see the schematic of one too.

Nick, I second Tom Cs' request. All the best, Tom.J

Sorry Nick. I completely forgot that you mentioned the manual on the phone last night.

Overworked and overtired. I was in a meeting most of the day yesterday. I was just leaving when I called you around 9 or 9:30? I think. Idk lol

I'm sleeping in Friday, Saturday, and Sunday.

No worries, I’m just ribbing you.

Yes, I would be interested in seeing the TM-21 manual, too, to compare to my TM-10 schematic. Just curious about how they differ.

Regards,

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

Check out the article introducing the monitor in RCA's Broadcast News.

Definitely not a run of the mill consumer roundie in a metal cabinet...

The TM 21 was a wonderful monitor. At WHTN TV, we used one for many years, in a High band TRT 1B RCA video tape recorder. Yes, I said High Band, thanks to a high band conversion kit made by Allen Electronics. The hetrodyne high band color was nearly as good as our RCA TR 70 machines. Steven Allen was a mad genius!

Broadcast News:
"..the upper section of the front panel is hinged at the bottom, so that it can be dropped forward to permit convenient replacement of the kinescope"

Good to keep a stock of spare glass-metal-glass CRTs back then;)

Two versions of the TM21 were made.
 

The early one had a metal CRT. The later ones had a glass CRT. The attached picture is the metal one but I saw in the '66 terminal equipment catalog that they had switched over to the glass tube.
They're pretty reliable. The only thing I ever did was replace the horizontal output tubes once in the 2 years I was there.
That's the aural side of the TT25BL transmitter next to it.

I knew a guy who had a TM-21, but he parted it out for the transformers and other parts for his tube audio hobby. :thumbsdn:

The unit he had used a glass CRT. I assume it was a 21CYP22, because it had 2 anode connection buttons on it.

All the documentation I can find shows that the TM-21 was first built with 21AXP22As, then the second run was built with the 21CYP22A, the third run built with 21FBP22s, and finally the fourth run was built with 21FJP22s.

In theory, you should be able to take a fourth run monitor (like the one I'm buying), swap out the anode lead, add a piece of external safety glass, and pop in a 21CYP22A or 21FBP22. I intend to do so.

Did anybody say TRT-1b?
 

I know its not part of the thread but I thought I'd show a picture of one for you guys who have no idea of what he's talking about. This one is Allenized also. But it was heterodyne color unlike the direct color from the TR-70 machines next to it. There are two more racks for the servo that are not visible in this picture.
We used a Conrac CYA monitor in the tape room. This picture is from early 76. In May of '76 we installed our first TCR-100.

Ben, Here's an RCA ad for the TM-21. Get some help when moving that beast.

-Steve D.