Merry Christmas!

[Ralph S]

I thought you might like to see the photo we used on our company Christmas card. The Santa on the DuMont RA 108A was actually reproduced live on the 19AP4 at the time the photo was shot. (The video came from an Hitachi Z2000 modulated to channel 3 on the DuMont.) The mic is an RCA 77-DX and the camera is a Mitchell NC sporting a real 40mm Bausch & Lomb CinemaScope lens. Merry Christmas to all.

[RCAkid]

Merry Christmas to you too!

That is way cool!

I have a 103 that has the 45rpm turntable in it as well and while I do get a picture and great sound from the radio/turntable, it is in dire need of restoration as it cannot maintain hv for long as the set heats up.

Anyway, I was wondering, when you did the restore on your 103, was it horribley complicated or just tedious. I have never seen such a massive chassis and it seems kinda daunting.

Any tips about the crt, things to look out for when retoring would be greatly appreciated.

Again, Merry Christmas and a Happy New Year!

[Ralph S]

Hi RCAkid:
First: There is no question that the RA108 is a big, dual chassis job. Thirty-six tubes and lots of caps and electrolytics (and some resistors) that needed replacing to make those tube go. In addition, some rather strangely marked caps which are noted in the schematic as 1.5 ohms @ 60 cycles, 6vdc. This works out to roughly 1800 ufd@6vdc, but this can stump you if you haven't run into it before.

Second: The picture tube on this set had seen better days and required some serious rejuvenation before it would put out anything resembling a decent picture; even then it's performance was marginal. I put a search file on ebay for a replacement 19AP4 and eventually one came up that turned out to be an RCA NOS 19AP4B - never used, ever. A great find with a "but..." The "but" was that the glass bell (post the metal cone) was slightly longer than the original DuMont tube and the deflection yoke and focus coil had to be pushed as far forward as possible but I still had/have some shading around the edges of the picture. Before I got the RCA tube I talked to Scotty at Hawkeye about regunning the DuMont tube, but I know he was hesitant to do the job given that the tube is a metal/glass combo and might not take the stress of the rebuild.

Another gotcha not mentioned in two above was this: Before I got the RCA tube I wanted to get the raster rotation right but the original yoke on this set had locked on to the Dumont tube and I could not adjust it. Eventually I had to literally cut it off the neck of the tube and replace it with another one I found on the internet. Looking back at this I might have just loosened the front clamps on the crt and rotated the whole tube and yoke to get it right, but since I knew that was going to have to replace the tube with a rebuild or NOS it made sense to solve this problem directly: remove and replace the yoke.

Finally: The set puts out remarkably good pictures and sound. I'm happy with the results and use it every weekday. Visitors love watching it and complement the quality of the set.

PS: I've just recently completed a RA 103 (Rumson). Scotty did do a rebuild on this set's all glass crt. The schematic calls for a 12QP4 but that's not what's in this set. This one appears to be an early evaluation crt with an unusual number and split cathode. Scotty had his gun rebuilders actually rebuild the complete gun assembly to match how it was originally done and it works beautifully! When I get back in the office (after the holidays) I'll dig up the number of the tube and post it here.

If you've got any other questions, just ask. Best wishes to all!

[Dan Starnes]

Love the photo and Merry Christmas to you!
Dan

[old_tv_nut]

Neato! Merry Christmas to you!

[Dave S]

And Merry Christmas to you!

Here's the card my daughter drew for me when she was 14 (she's 21 now -- I've gotten a lot of mileage out of this card!)



--Dave