Started checking voltages and they look good. Turned the brightness down a little and got a distorded picture. The brightness was wiping out the picture. I have to turn it up high cause the tube is almost dead.

Here is a video of what is doing:

Looks like your horizontal oscilator is way off frequency.
Bill Cahill

Congratulations on making it this far There's a horizontal oscillator adjustment slug on the back of the set. On the other side of the same coil, under the chassis there's another adjustable slug for setting the synchroglide lock. It's best to have a scope handy for making that adjustment. The Riders and Sams service info describes how to do it.

I got a scope. But its an older 1970s B&k. So it doesn't show the frequency like newer scopes. So I need to adjust it to match the wave forms in riders?

Yes, you will use the scope to view the horizontal waveform. I use an older B & K, too -- works fine.

As bandersen noted, both Riders (page 20) and Sams (page 12) describe the procedure.

Phil Nelson

I hooked up my scope. And got it adjusted and got a great picture now. I'll post pics later. But my horizontal will not come out of hold when i adjust the horizontal hold, full left or right. I know thats not a bad thing. But its weird.

Yay!

Some early horizontal systems are indeed that stable. My DuMont RA-103 doesn't even have a horizontal hold control in front. It's located on the rear of the chassis, which struck me as hubris on the designer's part until I played the TV.

Phil Nelson

It uses the synchro-phase circuit, which is very stable. At it's best, throw horizzontal hold off, try switching channels. Picture should go into lines. At peak adjustment, middle setting of control is most stable.

On the '50 models they had a different phase circuit, with a single coil on back. You adjust that coil for stability while changing channels. It also works amazingly well. My 21D1 chassis uses this circuit, and, it's amazingly stable.
I think RCA was the first of a more difficult version in their '46 models.
Bill Cahill

What is your signal source?

Phil Nelson

VCR

I need to hook a dvd player and rf modulator like my porthole

I haven't hooked up a dvd player yet. But the hum only happens when I have a video playing. When i hit the stop button on the vcr the hum goes away, but the vcr stays on. I didn't have the hum problem before I adjusted the horizontal oscillater, Could it be a intercarrier buzz problem like I had on my porthole?

I got me a good 10BP4, high voltage cage, and a couple knobs. I have done some cleaning on the bakelite cabinet today. I hope to have the chassis back in the cabinet this weekend.

Cool, I hope you get a nice bright picture.

I would hook up the DVD player this time, to eliminate the VCR as a trouble source. My son loves to collect old VHS tapes, and I have heard some awful sounds when the tape or the player (or both) are funky.

Phil Nelson

I hooked up the dvd player now and it sounds great.

Got the chassis back in the cabinet

Still need a inner brass knob and some better cleaning of the bakelite cabinet.





This is how I mounted my new speaker, audio transformer, filter choke, and power resistor. I mounted it like this so if I ever found an original speaker. I can pop this out easy and put in an original



Sitting on top of my porthole. I have a splitter come from the rf modulator and dvd player

The following is all moot conjecture if you'll be replacing the CRT in any event, but it strikes me as doubtful that the transformer added on to the rear apron of the chassis constitutes a "homemade brightener." I'm betting that it was added to isolate the CRT's filament connection from ground to eliminate the effects of a heater to cathode short in the CRT. Brighteners were a dime a dozen, but not all provided isolation.
The add-on transformer would have to have had some weird windings to make an effective brightener.

Nice set! I just picked up one of these today. 100% complete, but with a big crack down the right side of the bakelite case. Any suggestions for how I might go about doing a decent looking repair on the crack? I thought perhaps a careful application of JB Weld and a belt clamp. Comments?

Hi all !! I jsut bought this Admiral 12" tabletop tv for $10 It has 2 problems:1, the 5u4's plates get hot
unless I pull the seaker plug then it goes back to normal.also the main filter can gets rather warm .
help! love this nic lady