dumont ra-103

[stusnyder]

Just picked this up today from vk member kramden66. He had recapped it several years ago. Got it in the house and plugged it in. Picked up several stations on the fm band. Did not hook a vcr up to it yet, but it has a raster. Magic eye tube is lit but dim.
Cabinet has a burn mark in the top, and other scrapes. I'm going to have to at least strip the sides and top.

[M3-SRT8]

That's a DuMont RA-103D. Nice Televisor.

If you are going to strip it, I hope you know how. It's hard to partially strip a cabinet and match it with the unstripped part. But, if you can, and really feel it needs it, then go right ahead.

If you leave it alone and just give it a good polishing, that's ok, too.

Here's one of mine, fully restored. The finish was not stripped, just rubbed. Works great.

[oldtvsandtoy]

Can I ask what you rubbed it with. It came out very nice.

[stusnyder]

Forgot to mention I also got the wooden stand with it also.

[M3-SRT8]

Originally Posted by oldtvsandtoy

Can I ask what you rubbed it with. It came out very nice.

Howard's Restore-A-Finish, the Mahogany Formula. Just follow the instructions, and proceed slowly. Careful around the cabinet's edges, decals, etc.

[stusnyder]

Finished reapping this. Now I got a double vertical picture. Horizonal does not want to lock. Any pointers where to look? Tubes all test at least 80%, vertical osc had some way off spec resistors which were replaced.

[Electronic M]

I'd scope the output of the synch seperator first, as that could be responsible in part for both issues.

[RDusel]

Glad you picked that set up. I bought 5 TV's from Mike (Kramden66) he had some interesting sets that were going to be sold on Craigslist if not bought by VK and ARF members. I passed on that particular set as I have the Dumont Doghouse RA103 and they are very similar. Neat that you got the stand as well.
Plus those Dumonts weigh a ton and I hate moving them.
One thing to be careful of.. In my RA103 there are a few high precision capacitors used for the horizontal and vertical oscillators that look like old dogbone resistors instead of caps. One of mine had a hairline crack and it caused the horizontal oscillator to run at the wrong speed. You might have the same issue.
Hope this helps!
Rob

[stusnyder]

I figured out the horiz and vertical sync problem, there was a ground missing on the v16 6sj7 2nd sync clipper. One fixed that, horiz and vertical both lock.
Got a watchable pic, but awful snowy. Tomorrow I'm going into the tuner and check the components in there.

[zenith2134]

I bet an RA103 has a very good tuner in it. Sets this old usually need extensive cleaning as you probably know. On my '53 Admiral 16R12 the mechanism for vhf fine tuning didn't feel right mechanically and a quick regreasing of the endshaft fixed that. The RF and IF was well within spec however. Sometimes simple things help a lot.

[Phil Nelson]

My RA-103 article has a section about cleaning the tuner:

http://antiqueradio.org/DuMontRA-103Television.htm

A snowy picture could also result from other causes, of course.

Regards,

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

[old_coot88]

Originally Posted by stusnyder

...Got a watchable pic, but awful snowy. Tomorrow I'm going into the tuner and check the components in there.

Be sure and check the ant. input coils for continuity, on the chance that one could have been popped by the spike from a nearby lightning strike.

[David Roper]

And just in case you didn't know, don't use a balun, connect directly to 75 ohm cable.

[stusnyder]

Originally Posted by David Roper

And just in case you didn't know, don't use a balun, connect directly to 75 ohm cable.

You mean the device that has the threaded coax connector on one end, and 2 wires coming out the other end?

I found 1 resistor out of spec in the tuner. I got a better picture, but don't get full vertical height, and the sound does not match the best picture.