Dumont C100 Roundie (ETF 2009 Auction Score)

[jshorva65]

Here's the Dumont C100 that I scored at the Live Auction at the 2009 ETF Convention. Working toward building my roundie collection back up after regrettably having sold some of them a few years ago. That mistake was motivated by grief and some temporary financial hardship, as most here recall.



After moving the set into the house, removing the Horizontal Output tube, and doing a precautionary Soft Start with the Variac, I put the Output tube back in, powered up, degaussed, did touch-up static convergence and a grayscale setup and the set is in what I'll call "above average" working order. As shown, the picture is off-center vertically by about 1-1/2 inches with no means of adjustment since some previous "repair" shop apparently improvised a fix for a bad 10-ohm 2-watt Vert. Centering control by removing the pot and completing the circuit with some fixed resistors. Once I've tracked down a replacement, I'll install it, check IF and Chroma response with the B&K 415, and optimize everything with the GTE/Sylvania CK3000 test rig on the bench before reinstalling the chassis to put the set on permanent display. In this pic, Jamie and I pose with the set at the ETF.



Here are two pics of the set in operation before repair of the Vert. Centering pot issue. I'll probably check with Moyer's first to find the part. Anyone know of any other good sources for a Vertical Centering pot for this set (an RCA CTC-11 clone)?

[Phil Nelson]

That one really caught my eye, too. Looked like there was not a scratch on it.

Enjoy!

Phil Nelson

[zenithfan1]

Hey! I'm glad to see that CRT came back nicely on the blue gun, looks to be holding well. I was a bit worried when we tested it. Congrats on a great score!

[jshorva65]

Thanks, Phil. The only blemishes on the finish are so small that they're only visible upon close inspection and could be spot-repaired by Todd (my Cabinet Specialist) quite easily.

I've also got some 300mA fuses on order to add one to the Horiz. Output cathode circuit while I'm in there to replace the Vert. Centering pot. Looks like the Sweep circuit and Regulator are aligned nicely since it doesn't bloom at high brightness as color sets tend to do if the current hasn't been checked and adjusted recently. Still, I'll be checking all the operating parameters while I've got the set open for servicing and will be keeping the operating hours minimal until I've taken the precaution of fusing the output cathode lead.

[bgadow]

Can you get an RCA part number for that control? (from a CTC-11 Sams?) Given enough time I could look it up. I have a limited selection of NOS RCA parts, most too new but you never know. And maybe with a part # Moyers could find it?

[Robert Grant]

I had been eyeing that set quite a bit myself, but as soon as the auction started, it was way out my league.

I did make a do-able "score", however - a 21" Zenith B&W very much like the one I did some of my best DXing on when I was a teenager.

[John Folsom]

Check Surplus Sales of Nebraska for a pot. They have a pretty good selection.