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

Kevin Kuehn · #1 10-20-2011, 01:47 PM

My son and I went and picked this one up last night. The owner’s house sale had closed this week and this TV was scheduled for demolition tonight. The guy actually said he was going to break it up with a big maul and put it in the trash. So all it cost was $20 in gas and a little back pain. The cabinet is in generally rough condition, yet reasonabaly restorable. CRT condition is still up in the air. I'm getting intermittent emission, I suspect because there are broken wires under that base cap (heater is changing brightness). I'm pretty sure I can replace the tube base and fix that. Won't know how good the tube is until that happens. Maybe it's more realistic to view this as a parts donor for someone’s more worthy set. Anyone know of a spare right hand door, and a set of knobs?

Kevin Kuehn · #2 10-20-2011, 01:52 PM

One last picture.

Kevin Kuehn · #3 10-20-2011, 01:55 PM

Oh, forgot to mention. The owner told us he brought this home from a TV repair shop he worked in back in the early 80's. Said he had planned to restore it, but then Life got in the way. So likely most of the damage is TV shop rash, the top looks like it was used as a work bench, also that nice selection of knobs on the set.

Electronic M · #4 10-20-2011, 05:13 PM

You may be able to get by on the CRT reheating the solder on the pins, and glueing the original base back together.

If you can get knobs, but not doors you could always take the remaining door off, and either leave it that way or make/get new ones for a semi-permanant solution.

Kevin Kuehn · #5 10-20-2011, 07:42 PM

I decided to pull the broken CRT base off. Everything seems to be still in tact under there. I tinned the leads and soldered on strands of wire to use as pigtails, in order to pull the wires through the pins on a new base. I cleaned up a base from a useless series string brightener. Made a dry run before mixing epoxy.

Kevin Kuehn · #6 10-20-2011, 07:54 PM

I mixed up some black epoxy and stuck the base back on the neck. I have a table leaf leaning against it until the epoxy sets. I used 30 minute epoxy so I'll probably have to wait till morning for it to get good and hard.

bandersen · #7 10-20-2011, 08:46 PM

Great score and great job on the CRT base

I didn't know you could get black epoxy or did you add your own pigment ?

Kevin Kuehn · #8 10-21-2011, 12:57 AM

Quote:

Originally Posted by bandersen

Great score and great job on the CRT base

I didn't know you could get black epoxy or did you add your own pigment ?

Thanks. I'm keeping my fingers crossed that the CRT will show a little life.

I did put some pigment in the epoxy. I also mixed in some very fine milled fiberglass for strenth and to thicken up the epoxy. The stuff just loves to slide downhill.

How bout I run the cabinet down for a quickie refinish?

I'm not really feeling motivated to make sawdust.

bandersen · #9 10-21-2011, 01:40 AM

Hmmm, I wonder how well that would work to fill voids in broken bakelite ?

Quote:

Originally Posted by Kevin Kuehn

... How bout I run the cabinet down for a quickie refinish?

I'm not really feeling motivated to make sawdust.

That actually looks like a fairly easy refinish. That old lacquer just mels off with even mild strippers. Then some grain filler, minwax red mahogany stain and some lacquer. Looks like the controls area is in good enough shape to just touch up and preserve the decals.

Not that I'm up for doing it - at least not until next year. It's way too cold

BTW What CRT is that ?

Kevin Kuehn · #10 10-21-2011, 02:05 AM

Quote:

Originally Posted by bandersen

Hmmm, I wonder how well that would work to fill voids in broken bakelite ?

That actually looks like a fairly easy refinish. That old lacquer just mels off with even mild strippers. Then some grain filler, minwax red mahogany stain and some lacquer. Looks like the controls area is in good enough shape to just touch up and preserve the decals.

Not that I'm up for doing it - at least not until next year. It's way too cold

BTW What CRT is that ?

Yeah, I've filled Bakelite with epoxy. But in the past I actually sanded some Bakelite off the bottom of the cabinet and used that as color/filler. You could also grab just about any trashed Bakelite cabinet and grind Bakelite off of that. But I agree, the Blendal could work very well, at least once you get the color matching down. Ideally you'd want to use finishing resin epoxy for this; it cures much harder and sands more easily.

I assume the CRT is a 17AP4, but I've not found an actual number on it yet. There was a D on the end of the base- I assume that was for Dumont?

Depending on how the CRT tests, I may get motivated and refinish the cabinet this winter. I do have access to a nice abandoned shop that my Dad left us a couple years back...at least as long as Mom stays there, it's available. So far she insists on keeping heat in the place.

Says she doesn't want his tools to get cold. I can't wait to get older...

Penthode · #11 10-21-2011, 08:43 AM

Your set is a great find. I just picked up an RA112-A3 with exactly the same chassis except it has the 19AP4 round tube. This is my first set with the mallory "Inductuner". I did a google search on the inductuner and it seems it still is a current Mallory product!

http://www.duracap.com/inductuners/vhf400series.htm

The CRT in your set looks all glass and so I thought it would be either a 17AP4 or a 17BP4?

I have the same cabinet issues and it is too cold for refinishing so I'll concentrate on the chassis this fall.

It will be interesting to compare problems with these chassis's.

Tom Albrecht · #12 10-21-2011, 12:22 PM

I restored one of these about a month ago and sold the set. Fantastic performer! I'm restoring a Philco Predicta now, and it's really a shame to compare to the much older DuMont in terms of DC restoration (which the Predicta doesn't have), a nice linear scan (which Predictas are not good at), and video bandwidth (again no comparison). A decade of cost-cutting in TV design took its toll.

As Phil points out, the one I worked on had a 17BP4, which may well have been the factory original. Back cover had a very shallow dome, which did not look like aftermarket modification (dome was riveted in place).

The one I restored can be seen here: http://www.radiomuseum.org/r/dumont_...ra_113_b3.html

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

Kevin Kuehn · #13 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 · #14 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 · #15 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.