The Family DuMont

[bandersen]

Yeah, I was quite surprised to discover that while restoring an RA-113. I have a GE-802 with a beefy switch that cuts juice to most of the set while not in TV mode.

[old_coot88]

Cary,
Congrads on the successful power up. There is one paper cap i'd heartily recommend replacing as the first order of business. That's the coupling cap going to the control grid (G1) of the HO tube. The slightest leakage in this cap will cause the tube to overconduct, shortening its longevity.
If the tube is 6BG6, G1 is pin 5.



OOPs! Senior moment. Looks like you've already done a recapping. Presumably you got that one already.

[M3-SRT8]

Hi Cary,

I just 'tuned in' to this thread. Congratulations on resurrecting the Dumont. Not an easy first project.

I have a soft spot for DuMonts, obviously...

[CaryLee]

Turns out the rheostat that controls the focus is toast. About a third of the wire winds are eaten through.

I did hook up an old VCR/DVD combo with a built in RF output and was able to get a blurry picture..so that's good news.

Any hints on where I can find a 1200 OHM 25 watt ceramic rheostat with a long shaft? The Clarostat part number is RTV-220.

Photo soon...

[M3-SRT8]

Originally Posted by CaryLee

Turns out the rheostat that controls the focus is toast. About a third of the wire winds are eaten through.

I did hook up an old VCR/DVD combo with a built in RF output and was able to get a blurry picture..so that's good news.

Any hints on where I can find a 1200 OHM 25 watt ceramic rheostat with a long shaft? The Clarostat part number is RTV-220.

Photo soon...

Yup. Surplus Sales of Nebraska.

There's a 1k 25w and a 1.5k ?w on this page:

http://www.surplussales.com/Potentio...sRheost-4.html

Focus Controls are a soft spot on these old DuMonts.

[M3-SRT8]

Ooops. See you've already caught the SS of N page.

I bought a bunch of those a couple of years ago to keep in stock.

You can hang a 25ww resistor off the end of the 1k Control to gain a little more range, if need be.

[CaryLee]

Originally Posted by M3-SRT8

Hi Cary,

I just 'tuned in' to this thread. Congratulations on resurrecting the Dumont. Not an easy first project.

I have a soft spot for DuMonts, obviously...

Nice stuff! I hope to get as good a picture out of mine eventually. I just determined my focus control rheostat is a goner..

[CaryLee]

The SAMS calls for a 1200 ohm 25 watt rheostat...

Surplus Sales has a 1000 ohm 25 watt, left side of the page on link below..for $8..would that be close enough?

http://www.surplussales.com/Potentio...sRheost-4.html

[Phil Nelson]

Originally Posted by CaryLee

Surplus Sales has a 1000 ohm 25 watt, left side of the page on link below..for $8..would that be close enough?[/url]

That's exactly what I installed in my RA-113.



The shaft was too long, so I cut it down and filed a flat area to fit the knob.

Phil Nelson

[CaryLee]

Outstanding! Thanks for the input..I'll get a couple of those rheostats ordered so I have a spare around.

Restrung the tuner dial tonight. The list of "to-do's" gets shorter!

I called my mother a couple nights ago and told her "the DuMont lives!". She remembered when I hefted that sucker out of grandma's house and into her van, by myself, about 25 years ago. She used to watch that TV when she was a little girl. When she comes out to New Mexico for a visit later this year, it looks like she'll be able to watch it again. That's pretty cool.