'50's 17" RCA B&W

[dieseljeep]

Originally Posted by peverett

It looks like RCA used the horrible plastic on the yoke that falls apart over time. This seems to be common on RCA and Zenith sets of that time period.

I don't think that is the orignal yoke. RCA yokes looked slightly different. Take the yoke cover and centering device from the Olympic that you acquired. That thing isn't worth spending time and money on. They were lousy sets and there's too many parts missing.

[radiotvnut]

Originally Posted by dieseljeep

I don't think that is the orignal yoke. RCA yokes looked slightly different. Take the yoke cover and centering device from the Olympic that you acquired. That thing isn't worth spending time and money on. They were lousy sets and there's too many parts missing.

Actually, the one on the Olympic is starting to come apart and I don't think it would hold up to being disturbed. I'll either have to find a good yoke cover or make one.

I did begin the recap tonight and this set has been worked on several times. First off, one chassis mounting nut and a mounting screw are missing. Also, only one of the cabinet back mounting clips remains. Once I got the chassis out, I discovered where some resistors had been changed (one in the power supply and one in the horizontal output circuit). There were also some early orange drop caps that had obviously been replaced. This chassis uses a mix of point-to-point wiring and PC boards. Unfortunately, the PC boards are mounted in such a way that they have to be dismounted from the main chassis in order to "properly" replace components. Of course, one could do like the previouse technician did and cut off the old part from the top of the board, bend the leads into a "J" hook, mount the new part on the topside of the board, crimp the leads together, and solder. I'd like to replace the parts "correctly"; but, I'll just have to see how much trouble it is to remove the boards.

BTW, this will no longer be a fully American TV. For the exception of one 1600V Sprague/Vishay Orange Drop, the rest of the caps were made in either China, India, Taiwan, Malaysia, or Japan. At least they appear to be of good quality.

As far as the Olympic, I may play around with it; but, it won't be anything I invest a great deal of time or money into restoring. Especially since it's missing parts and has a weak CRT.

[radiotvnut]

I recapped the video/sync board and I at first gave in to temptation to "J hook" the parts on the top side of the board. My temptation soon went in another direction when I discovered that some of the caps that had already been replaced were loose on the foil side of the board. After seeing that, I was forced to unsolder the board and remove one wire in order to gain access to the underside. Since I had the board out, I replaced the caps the "correct" way. Fortunately, I didn't have any trouble with the traces lifting from the board. It should be interesting to see what all is involved in getting the other boards to an accessible position. Like most portables of that era, they crammed what would normally be found on a large 21" console chassis into a small portable chassis.

[dieseljeep]

I never used that method of hooking onto existing leads. Those boards are easy to remove to get at the print side. The sets that I worked on all had UHF tuners and a cascode RF amp. The UHF models also had a range control.

[cbenham]

Originally Posted by Phil Nelson

It's just marketing-speak, like "Sky Champion" or "Mighty Monarch of the Air."

In legal terms, this is called puffery. You can't sue a company for using such silly language, because nobody knows exactly what it means in the first place.

Phil Nelson

But was there ever anyone at RCA Victor named D.D. Cole?
His name appears on the "Golden Throat" sticker.

[radiotvnut]

The horizontal sync/driver board is now recapped and I'm now on the vertical sweep board. I can tell that this one is going to be a little more difficult to get to as there are several wires that will need to be disconnected before I can get the board out far enough to replace all the caps. At some point, someone did a sloppy job of recapping this board with a mix of Sprague (black) and Cornell-Dublier (green) tubular paper caps. I did manage to replace one cap before deciding to call it a night.

After I'm finished with this board, it will be time to do the sound board.

After that, maybe my terminal strips from AES will have arrived and I can replace the electrolytics and the selenium rectifiers. I've not yet decided if I'm going to attempt to restuff the old electrolytic cans or if I'm going to wire the new caps behind the chassis with the old cans left in place for looks.

The more I dig into this set, the more I discover that it spent lots of time in a repair shop.

[radiotvnut]

The vertical board has been recapped; which, was very interesting. First, I had to unsolder four wires from the chassis, in order to be able to slide the board out enough to gain access to everything. With the aid of a battery operated work light, I flipped the chassis on one side to desolder and remove a cap. Then, I would flip the chassis over on the other side and reposition the light. After poking the new cap through the holes, I'd flip the chassis back on the other side, reposition the light, solder in the new cap, cut off the excess leads, and repeat the process. Tomorrow, I'll re-mount the board to the chassis and resolder the four wires that I had to remove.

I still have to do the audio board, the electrolytics, the rectifiers, and any other chassis mounted caps. At this point, I'm starting to see some light at the end of the tunnel.

[radiotvnut]

Well, I think I'm getting close.

The terminal strips came in today and I simply disconnected the old filter cans and wired individual sections behind the chassis.

I disconnected the two selenium rectifiers; but, left them physically mounted to the chassis. I soldered the terminal strips for the new rectifiers, using the center mounting lug of the terminal strip, to one of the now disconnected terminals of the selenium rectifiers. At this point, I have not added a series dropping resistor to the output of the voltage doubler. Once I'm done with everything else, I'll power up the chassis so that I can check the output voltage against the schematic. Then, I'll add whatever value resistor is needed to bring down the voltage to the schematic value.

To remove the audio board, it was necessary to unbolt a portion of the chassis. After that, I was able to desolder the PC board from the metal piece that was unscrewed from the chassis. The caps have been replaced on that board and all that is left to do is re-install the board.

There was one cap, between the plate and screen grid of the audio output tube, that I forgot to order (.0033uf, 1KV). I don't know why they would use a 1KV cap in such an application and since all I had on hand were 630V caps, that's what I used. Had it been in a deflection circuit, I would have waited to get a 1KV cap. I suppose I could wire two .0068uf, 630V caps in series to give me the correct working voltage.

Soon, I'll post pictures so that you can see my sloppy repair work (although not as sloppy as what the previous guy did).

[radiotvnut]

I powered up the chassis, out of the TV, and it looks like the B+ voltage is only about 10 volts higher that what is specified on the schematic. So, I don't think a resistor is necessary.

The first two times I powered up the chassis, I had no HV. When I connected my meter to the HOT grid to check the drive voltage, the HV came back and has not gone away since. I suspect a bad solder connection and, tomorrow, I'll go back over my work in that area. The only voltage that was a little low was the HOT grid drive. The schematic specifies -23 volts and I'm only getting -15 volts. The other HOT voltages check fine and I have not yet checked the HV.

When I pulled the yoke, I discovered that it was a Merit replacement. And, what was left of the housing crumbled into little pieces.

Also, the aquadag coating is flaking off the CRT like crazy. Some time ago, I think I remember reading something about aquadag paint that could be used on CRT's. Is that so?

The CRT looks original; but, this set has spent a lot of time on the repair bench during it's life.

On sets like this, I wish I had one of those '50's era B&W CRT test tubes with the extension cables for the HV, CRT socket, and yoke.

[GeorgeJetson]

Originally Posted by cbenham

But was there ever anyone at RCA Victor named D.D. Cole?
His name appears on the "Golden Throat" sticker.

I've also seen his name on the "eye witness" sticker.

[radiotvnut]

Here's my sloppy repair work. I'm about ready to connect everything up for a test.

[DaveWM]

wonder whats up with those burnt looking micas?

[radiotvnut]

Originally Posted by DaveWM

wonder whats up with those burnt looking micas?

I wondered the same thing. I have an idea that the previous technician let a soldering iron or soldering gun get too close to them. I also found some wiring with slightly melted insulation that was probably done by a soldering iron. In a set like this, making such mistakes would not be difficult if one didn't pay attention to what they were doing. And, we all know how sloppy some techinicians could be. The objective was usually not neatness. It was usually "get it fixed ASAP, get paid, and get it out the door". I can see how it would be easy to have that attitude if you had 50 TV's waiting their turn for the bench.

[radiotvnut]

I now have a picture! Obviously, it's not centered and I need to adjust the vertical height and linearity. However, it looks much better than it did when I started (I really think this TV likes the new caps). I still need to test the tubes and replace any defective ones. Also, the vertical sync circuit will need a little more attention. During a scene change or between commercials, the picture will sometimes roll once. I also found a mica cap on the horizontal board that had a loose connection; so, that was likely the reason for the intermittent HV. I even gave it the 3 minute Maury Povich test and even though her "babydaddy" wasn't who she thought it was and there was quite a scene backstage, the TV still kept going. And, to think they took off RTV programming in order to have more of this kind of (bleep).

[bandersen]

You might call your work "sloppy", but it looks pretty good to me Better yet - the sets working

Are you gonna put those old parts up on ebay ? Maybe the audiophools will like them