In the Admiral 19A11, what's the deal with these rear-panel potentiometers (like Focus) with the nylon shafts and innards? They're all really, really sticky. I took apart the Focus pot to see if it was frozen with gunk or melted. Looks like new. I cleaned it anyway, and applied a little electronic lubricant. It's still so stiff that it feels like I'm going to ruin the shaft when turning it.

http://antiqueradio.org/art/Admiral19A12FocusPotentiometer.jpg

Is there some magical lube that will make these turn normally?

On the positive side, it looks like there's some life in the CRT. All I've done so far is replace the power-supply electrolytics and the 6KV-rated caps.

http://antiqueradio.org/art/Admiral19A12FirstImage.jpg

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

If it's the shaft that's binding, it may have swelled over the years. I'd try some fine emery paper on it to reduce it a little followed by a good cleaning and relubing.

Looks like you've got a GOOD 7JP4 there...

Yes, it's the shaft that binds, and only in the enclosed part (the portion that hangs out beyond the chassis doesn't bind at all). I didn't know that nylon can swell. Sanding sounds worth a try.

Regards,

Phil Nelson

I have the same situation with the 17T1. Focus knob is very tight. Curiously, the adjacent horiz. cent. knob is less stiff and the vert. cent. knob doesn't bind at all. I think maybe that corner of chassis is hotter.

Same deal with the three nylon pots on my set. Tight, tighter, tightest. Swelling from heat would make sense.

Phil Nelson

I'd guess that the most probable suspect is the nylon, but another thought, might be the bearing has swollen.

Pot metal is well known to swell with age and I'd assume that these bearings probably were cast and not machined.

On some pot metal assembles from the 1920's, I've run into swelling pot metal that has pinched the steel shafts after long storage. I found it easier to ream the bearing than to polish the shaft and either seems to work equally well.

You know, my first thought was swelling of the Nylon. But reading "earlyfilm's" suggestion of swelled pot metal, that makes sense. And, it may be easy to ream it out with the appropriate sized drill.

Just a thought.

Does anyone happen to have a scan of the Sams manual (59-2) for this model? My library doesn't have the paper version and they cancelled their subscription that formerly let me download manuals for free.

I got the Riders manual from the ETF archive, but the more docs the better :)

You can send me email via http://antiqueradio.org/contact.htm .

Phil Nelson

I just emailed it to you. Enjoy.
- Winky

Thanks!!

Phil Nelson

The Admiral's looking better, after a basic recap and some new resistors.

http://antiqueradio.org/art/Admiral19A12ThirdImage.jpg

This set was somewhat recapped long ago, by the look of the replacement caps used. I found a couple of funky things and I wonder how well it worked at that stage, if at all. The picture tube was very crooked, as seen in the first photo. It's hard to imagine someone watching it very long in that condition.

Perhaps this is a later version. It has a vertical linearity control on the back panel that's not shown in either manual.

Phil Nelson

My 17A1 has the vertical linearity control, and I have this schematic showing the control on two 19A1 models, the 19A11 and 19A15. I have no idea where the schematic came from. It looks identical to the Wallace schematic with a slightly different drawing style.

https://lh4.googleusercontent.com/-FPCpvZKfn1A/UDcRDd23_sI/AAAAAAAAJ60/R2OwOlQS6lg/s800/Adm%252019A1%2520vert%2520lin.jpg

- Winky

Phil-

Some people have said that the 7JP4 TVs have mediocre pictures compared to bigger sets, but yours has as good a picture as I could imagine could be created on any 7-inch CRT. If any of my 7" sets look anywhere near that good when I restore them, I will be very happy. Nice job!

The picture quality on that set is fantastic. I wish my Tele-Tone looked that good. Inspiration to find a stronger 7JP4 for it for sure.
Keep up the good work :thmbsp:.

The picture is pleasing, considering what a simple design this TV has. None of my 7-inch TVs seems as bright as an electromagnetic-focus set using a 10BP4, etc., but perhaps that's the nature of the beast.

The focus ain't bad, but I think I will take that focus pot back out and free it up, now that I have a stable image to work with.

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

My RCA 730TV1 is the only 10" set I've restored so far but the 10BP4 in that has an absolutely amazing clear crisp image. I remember staring at it :drool: for hours after I had finished it and just being stunned at how good a 64 year old television looks.
Here's hoping that being able to adjust the focus will give you an even better picture than you already have.

Phil-

Some people have said that the 7JP4 TVs have mediocre pictures compared to bigger sets, but yours has as good a picture as I could imagine could be created on any 7-inch CRT. If any of my 7" sets look anywhere near that good when I restore them, I will be very happy. Nice job!

Electrostatic sets can look good when properly restored. Here is a picture from my Motorola 9VT1 with the 8BP4 electrostatic tube which is electrically identical to the 7JP4 except with an 8" screen. It will never look as good as an electromagnetic deflection set with an aluminized picture tube but for what it is it works well. Not bad for a 58 year old picture tube, eh?

Yes, that set looks good indeed.

The only two 7JP4 sets I have seen working were a Motorola that I did some repairs on in about 1980 when I had no idea I need to replace all of the capacitors (not surprisingly, it was still pretty bad even after a few new HV disc caps in the sweep circuits), and a Sentinel TV400 (or 400TV?) that worked well "as found" about the same time (before I knew not to power up old sets before replacing critical parts).

I have run out of significant things to fuss over, so I guess this project is nearly done.

Today, for fun I brought the Admiral out for a "Pepsi challenge" with my recently restored Philco 49-1240. I was expecting the 7JP4 to look dim and washed out next to the Philco's 12LP4, but it compares pretty well. These are unretouched daylight snapshots and both TVs are receiving OTA signal from my in-house transmitter on separate rabbit ears.

http://antiqueradio.org/art/Admiral19A12Philco49-1240Comparison1.jpg

http://antiqueradio.org/art/Admiral19A12Philco49-1240Comparison2.jpg

This TV had loads of retrace lines when I turned up the brightness to what seemed a desirable level, so I added this little blanking circuit that I read about a while ago.

http://antiqueradio.org/art/Admiral19A12RetraceLineBlankingCircuit.jpg

I don't know if this circuit is the optimum solution for this TV, but it made quite an improvement without noticeable side effects.

Now, if it only had DC restoration . . . :)

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

Phil, just be happy you've got what seems to be a VERY nice example, which works very well indeed. I DON'T think these l'il guys were ever sposed to last anywhere nearly as long as they have...

When I sat down to write an article about this set, I finally noticed that the label says 19A12, so I guess that's what I should call it:

http://antiqueradio.org/Admiral19A12Television.htm

I assume there were magazine ads featuring this set, but I haven't run across any yet.

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

The 1934 "Cleopatra", starring Claudette Colbert & directed by Cecil B. DeMille, a Paramount release. Nice touch, Phil! Warren William was quite good as Julius Caesar in this one too. Add Joseph Schildkraut & Sir C. Aubrey Smith & you've got a high octane cast of leads to start with. Excellent images on both sets, may I add.

Great restoration and writeup :thmbsp:

I haven't come cross any ads either, but it is shown in their 1949 catalog:

http://www.shedradios.com/ADMIRALA.HTML
http://www.shedradios.com/ADMIRAL4.HTML

19A11 = brown bakelite
19A12 = black bakelite
19A15 = maple wood

Thanks for the note on the model numbers. I modified the article to clarify that.

Cleopatra just happened to be playing on TCM when I snapped some photos. It has great visuals, but I was too busy taking photos and running back & forth to the computer to follow much of it. Perhaps they'll run it again when I have time to pay attention.

Phil Nelson

Phil, thanks for the superb article on the 19A12. When you get a chance, can you explain why the tubular HV caps are better than cheap ceramic disks?
-Winky

Using tubular caps in those HV coupling circuits seems to be the popular wisdom. I have never tried ceramic discs there to find out, but my understanding is that they may distort the scanning signals. What form that would take, I'm not sure. Perhaps anything from poor linearity to a scrambled picture.

As a rule, I don't use ceramic discs in any place where they were not originally used, especially in sweep circuits where high frequencies may beat them up.

I have a couple of other 7-inch sets waiting for restoration. If I ever get around to them, maybe I'll try substituting a couple of ceramic discs once the TV is working, just out of curiosity.

Phil Nelson

Years ago I used ceramic discs in my VT71 as that was all I could find. They worked fine for years and finally one went leaky. I used the ASC 6KV caps available today and they are fine too. The discs I used were damper circuit discs. My VT71 still has one in the high voltage filter circuit.
I recently was given some .002 12KV Potter brand tubular and will try them after I get my 9L1 Moto up and running. Has anyone heard of these Potter caps?

turned out really nice .

The capacitance of a ceramic cap varies with the applied voltage causing distortion in the sawtooth waveform. It's really not noticeable in the horizontal but may be in the vertical.

More info here: http://www.antiqueradios.com/forums/viewtopic.php?t=119878

The capacitance of a ceramic cap varies with the applied voltage causing distortion in the sawtooth waveform. It's really not noticeable in the horizontal but may be in the vertical.

More info here: http://www.antiqueradios.com/forums/viewtopic.php?t=119878

When I first restored my 9VT1 I used ceramic caps to replace the high voltage caps as that was all I could find and I did not know wehere to get the tubular ones. They worked fine except for the vertical. I could not get proper linearity until I doubled up the caps in the vertical circuit. It had me stumped for quite a while. I eventually replaced the ceramics with tubulars and would not attempt to use ceramics again in this application.

After reading your posts and looking at some of the links, I'm convinced not to go cheap with the HV caps. Especially when I compare Phil's 19A12 picture with what I had when I picked up the set two years ago.

https://lh6.googleusercontent.com/-TNcLvVBIZJs/UEgN2nvPHQI/AAAAAAAAJ8g/rDMQs7OLzOI/s800/Adm%252017T12%2520Picture.JPG

Thanks to All,
Winky