Interesting RCA commercial/hotel TV

[RetroHacker]

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