Dumont RA 113 B5 Find - Page 2 - Videokarma.org TV - Video

Kevin Kuehn · #16 10-21-2011, 01:02 PM

I see Phil's set only has the one jack, where mine has both phono in and video out.

Here's a picture of my dome, jacks and hopefully you can read the serial#

Kevin Kuehn · #17 10-21-2011, 01:06 PM

That dome is pretty crude, as in not very round. Plus the back is all perferated even upto the dome. Could be a later mod?

Kevin Kuehn · #18 10-21-2011, 01:19 PM

Quote:

Originally Posted by Tom Albrecht

Mine was the -B3 Revere in mahogany, just ever so slightly different than your -B5 Burlingame, which has little "legs."

Tom, your restoration was another part of why I brought this one home.

I think the guy I got it from even stole your description from your Radiomuseum posting, for his CL ad. At least it read word for word. I dread the cabinet restoration, but I’d really like to have the experience of watching this set.

holmesuser01 · #19 10-21-2011, 02:22 PM

I also have this same set, using a 17BP4, and has the little bump on the set back. Mine had a burned up power transformer, due to someone trying out the set in the past. I found the shorted capacitor on the first hunt, and aquired a transformer and chassis from a nice fellow in Rhode Island.

I've replaced a bunch of electrolytics in mine, so far, and now have sound thru the Inputuner to the speaker, and FM radio, clear as a bell! I'm running the set after each capacitor replacement, and was thoroughly surprised when the sound came on... full volume... due to the volume being up all the way... after a single capacitor replacement under the deflection circuitry area of the set. Still no picture, but I think I am hearing the vertical oscillator running... I'm not letting the HV come up, yet.

My set has the tube number on the underside of the CRT bell up near the screen.

Kevin Kuehn · #20 10-21-2011, 03:05 PM

Well unfortunately my CRT is not looking too promising. I’m getting a solid reading now, but it’s way towards the bottom of the bad scale. Even with the filament voltage at 8v, emission only rises to about 1/3 scale. Dropping the filament voltage back down, the emission takes a nose dive. I'll let it cook a couple days and see if it improves.

I think we’re to the point that we may have to get creative and start subbing newer CRT’s in our old sets, at least if we want to continue watching them on a regular basis. I’ve seen a couple NOS 17CRP4 available, but those are 90 degree electrostatic focus and they have a very low g2 voltage spec. I suppose they could be adapted to if we’re not too fussy about original circuitry.

Penthode · #21 10-21-2011, 03:29 PM

My 19AP4 was a rebuilt tube with an October 1964 label on it. I therefore had hope that it was good.

When I got the set home and tested it with my BK467, there was absolutely no emission. I tried coaxing it back to life and the emission improved slightly but was miserably low. I then gave the tube a rejuvenation burst.

Lo and behold the emission came right up and is now excellent, even on life test. This was a few weeks ago and I tested it again and the emission remains excellent.

Consider that the tube has been sitting dorment for probably forty years. I think it just needs to be woken up.

Kevin Kuehn · #22 10-21-2011, 04:06 PM

Quote:

Originally Posted by Penthode

Consider that the tube has been sitting dorment for probably forty years. I think it just needs to be woken up.

This one is now almost up to the bad/good line, but it's still on 8v. It did not respond to Rejuv 1. Is it bad to let it cook on 8v for a day? I figure no worse that putting a brightener on it.

VDC actually shows 17BP4's in stock, most likely in error. I've inquired about other tubes and they're not really there.

http://vdc.mybisi.com/product/17bp4

holmesuser01 · #23 10-21-2011, 07:03 PM

I'd sure be careful using a rejuvinator on an old tube so quickly. One shot can destroy a cathode. In my case, the rejuvination is the last resort. Let it cook for awhile.

Tom Albrecht · #24 10-21-2011, 08:53 PM

Quote:

Originally Posted by Kevin Kuehn

That dome is pretty crude, as in not very round. Plus the back is all perferated even upto the dome. Could be a later mod?

My guess is that the set and its back were originally designed for 17AP4, but midway through production, DuMont decided to use 17BP4. They did a factory rework on the backs, adding the dome. The backs had already been perforated in the area of the dome.

The tube label on the inside of my set specified 17BP4, so at least they updated the labels.

The tube in mine was an RCA, with very strong emission. Perhaps that was a replacement, with a DuMont 17BP4 being stock.

If this tube won't come to life, I don't think you will have much trouble finding another 17 inch tube. There are a lot of 17 inch sets out there that are far less worth saving than a DuMont. 17LP4 was a pretty common tube; not sure if it has the correct deflection angle.

I'm not so conservative on rejuvination. Had good success with it several times, and don't recall ever making a tube a lot worse. Some tubes simply won't rejuvinate, but I suspect they are beyond rescue no matter what.

If you're up to the good/bad line at 8 volts, however, you may be fine with a brightener now. I'm often surprised at how good the picture looks on tubes that test in the ? range.

Kevin Kuehn · #25 10-21-2011, 10:57 PM

Curiosity got the better of me, so I pulled the CRT. I'm guessing it's original to the set. I think someone watched this TV to death.

old_coot88 · #26 10-22-2011, 02:47 AM

Quote:

Originally Posted by holmesuser01

I'd sure be careful using a rejuvinator on an old tube so quickly. One shot can destroy a cathode. In my case, the rejuvination is the last resort. Let it cook for awhile.

Indeed. 110% spot on. With a 'juvination nine times out of ten the tube will be nice and bright for a week or two then go completely flat even with a brightener. Whereas a brightener alone will maintain it much longer.

Kevin Kuehn · #27 11-21-2011, 07:50 PM

Slowly poking away at this, I've been on a knob hunt for the last few weeks…

I while back I cleaned up the knobs that came with the set and realized that I had three possibly original to the set.

Then I received a few more Dumont knobs from Mike Koste (Gobs Of Knobs). Plus today I got another lead on a couple more knobs that should complete the controls.

Does anyone know of a way to remove the "brights" from these before soaking them in 409 cleaner? It sure would be nice to remove them to simplify polishing and re lacquer.

Phil Nelson · #28 11-22-2011, 04:52 PM

Most brights seem to be glued on. Unless they're already loose, trying to pry them out might do more harm than good.

Phil Nelson

Kevin Kuehn · #29 11-22-2011, 06:07 PM

Quote:

Originally Posted by Phil Nelson

Most brights seem to be glued on. Unless they're already loose, trying to pry them out might do more harm than good.

Phil Nelson

Yeh, plus I think these are pressed in too. I'm just paranoid that water will get under and then not being able to dry out, but I'll try not to worry about it.

wa2ise · #30 11-23-2011, 01:26 PM

Quote:

Originally Posted by Kevin Kuehn

Anyone know of a spare right hand door, and a set of knobs?

No, but on or more of those on your set look like Admiral knobs. Someone here may need them, so when you do get the correct knobs, please save the old knobs.