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Old 04-02-2016, 04:23 PM
RetroHacker RetroHacker is offline
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Interesting RCA commercial/hotel TV

This one followed me home recently - another curb find. Definitely not something you see every day, it's a commercial set, with a built in AM/FM radio.

I, of course, had to grab it. Attached are some pictures - it's pretty beat up, the control door is missing, and there's a scratch on the CRT (seriously, what is it with scratches - it seems like half the sets I find any more will have a scratch on the tube somewhere). Inside, the chassis appears to be a fairly ordinary hot chassis design, the radio being a separate unit. A panel on the back contains some volume limiter controls to restrict the maximum volume for the radio and TV, as well as some jacks for external speakers.

I fired it up, and, well, this one is a goner. I get sound and high voltage, the tuner works, but I get absolutely nothing on the screen. No light of any kind. Radio mode also doesn't work - the tuner lights up but no sound. Investigating further, I can't see the CRT filament lighting up. After running for a while, the neck of the tube isn't warm either.

I connected the tube to my CRT tester, and, my suspicions appear to be confirmed. That won't light the neck up either. I get zero emissions on all three guns, and the neck never gets warm. No shorts though. Interestingly enough, checking the continuity of the filament with my multimeter reports about 2 ohms. So... it would seem to not be burned out, but why won't it light? I'm really confused, I've never seen a filament in a modern CRT burn out - and, I'd expect it to go open if it did.

Very weird. Odd failure. Unusual TV.

-Ian
Attached Images
File Type: jpg rca_hotel_tv.jpg (97.3 KB, 78 views)
File Type: jpg rca_hotel_tv_inside.jpg (73.5 KB, 63 views)
File Type: jpg rca_hotel_tv_back.jpg (109.6 KB, 49 views)
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  #2  
Old 04-02-2016, 05:58 PM
zeno zeno is offline
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Instead of the usual round pins of older CRT's this one
probably uses spring contacts. Be sure they are not
cooked on both the CRT & socket end. This was very common
on older in line RCA CRT's especially when used in Admirals &
Maggies. Open filaments are VERY rare unless the CRT has
gone to air. In that case the neck will arc & light up blue
then probably go in to shut down.

73 Zeno
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Old 04-02-2016, 06:06 PM
RetroHacker RetroHacker is offline
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Yeah, I thought of that too - the contacts are good, and the pins of the CRT aren't damaged. Neither the CRT tester nor the TV will light up the filament, even when I rock the connector. Even tried bending the filament pins out a bit, to make better contact with the tube - no change.

-Ian
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Old 04-02-2016, 08:02 PM
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radiotvnut radiotvnut is offline
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The filament is powered from a winding on the flyback transformer and there is a small value resistor in the filament line. On all sets, it's a fairly common problem for this resistor to open. Of course, that still does not explain why it's not lighting up with the CRT tester (unless something is wrong with the tester or the socket).

The TV is likely an ex-hotel/motel set. In the '90's, we had some flophouse motels that still used some older RCA sets (late '70's-early '80's); but, those had either a standard two-knob tuner or a single knob varactor tuner (all of them had AM/FM radios). The older ones used a CTC97 chassis. The newer ones used CTC108 and CTC120's. Your set looks to have a CTC136 chassis.
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Old 04-03-2016, 03:45 PM
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vinljnkie vinljnkie is offline
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That dealer sticker on the back is from my home town and Gerken's is still in business! They have been around since 1964. http://www.gerkensinc.com/index.html
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Old 04-04-2016, 08:05 AM
zeno zeno is offline
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Quote:
Originally Posted by vinljnkie View Post
That dealer sticker on the back is from my home town and Gerken's is still in business! They have been around since 1964. http://www.gerkensinc.com/index.html
Amazing they have held out. Nashua I think is down to one
shop in the bad part of town. Very small one man opp. He gave
me all his Sams & lots of mostly crappy parts.
Used to be a shop on every corner it seemed.

73 Zeno
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Old 04-04-2016, 12:50 PM
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Jon A. Jon A. is offline
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Now that's a pretty cool RCA.

If the CRT neck board uses spring contacts and the CRT is indeed shot, save the plastic fitting on the neck. It will slip right onto another inline CRT with the same number of pins. The hard part will be getting the other one off. I checked the pin assignments of a spring contact adapter against an ordinary inline socket adapter (Sencore CR70 sockets 3 and 7 I think), perfect match.
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