An Emerson with a 19AP4??
 

http://rochester.craigslist.org/ele/4471969543.html

...at least I think that's a 19AP4?

Well, a similar looking model with no doors (model 675B; ch.120129-B)* used a 19 AP4, so I am guessing that your are correct.

jr

*Photofact 126-5

Already deleted off CL.......

.....Maybe The Captain beamed it up......

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Nope, weren't me....

Looks like it went to ebay......

http://www.ebay.com/itm/1950s-Era-Em...item2a3df28de0

Auction closed without bidders, so I'm driving to Rochester NY with my picture tube tester on Saturday. We'll see what happens :)

Don't forget the tester........:D

When I look up an Ebay listing, it shows other related listings. The people that are trying to sell those el-cheapo 5" B/W for ridiculous prices. :boring:

Well, brought my tester with, and at first the tube showed little signs of life. For the heck of it, I brought it up to about 7.8V on the tester, let it sit for maybe 30 seconds, and it deflected right up into the mid green. The set has an RCA Silverama 19AP4 in it. I think this tube with a little activation will be just fine :) .

Oh, and I got the set for $25 :)

I also got 2 huge boxes of Sams folders dating from about 1950-54 or so, along with factory Motorola, Philco, and GE service literature dating from 1948-54 or so, all for an additional $25. Not a bad day at all, I'd say :)

Here's some pics. Definitely much better than the shots I'd seen.....

I even came across the original owners manual in the literature I got. Now I don't know if I have the heart to part it out!

Looks like w/some CAREFUL work, maybe a little paint thinner/fine grit sand paper, the cabinet could look like new again..

Much too nice of a set to part out. Looks like a keeper to me.

I decided to keep them both, for the time being. Since the DuMont RA-110 that I have has apparently been fully restored chassis wise, I'll swap picture tubes to see what the DuMont will do. Then, depending on the result there, I'll either put the picture tube back in the Emerson and restore that, or let the Emerson sit until another 19AP4 crosses my path.

Just lugged the RA-110 into the basement along with all the guts from both sets. Guts or not, that DuMont is one HEAVY sob.....

I ran across a lot of Emerson's, but never a 19" roundie. It must be the last issue 19AP4, straight gun, no ion trap.
I've seen several 19" roundie sets, Admirals, RCA's and of course, Zenith Portholes. Emerson 19" roundies, must be rare. :scratch2:

Motorola used to make a 19 inch set. I wonder if it used the same tube?

I followed Bob Anderson's restoration thread on the Motorola 19K1 and it used the 19AP4.
IIRC, Zenith/Rauland, Dumont and RCA used the same designation. :scratch2:

Well viewing my current frustrations with my 730TV2 and the RA-110, I figured I'd set those aside for the moment and see what I can do with this set.

Much to my dismay, there are FIVE capacitors underneath with leads cut on the one end, one looks like it was just a sub to test something (sigh).

Okay, not impossible, just check out the schematics and see where they go, right? First one I started on I can't figure out. It's a .05 uF 400V with the foil side cut. It comes off of the vertical linearity pot. According to both the Sams and the factory Emerson schematic, this cap shouldn't be anywhere in the circuit. I have no idea where it goes or why it would even be there.

Ideas?

I bet it was a replacement, maybe someone replaced a buncha caps looking
to solve a problem, and just left the old ones hanging there..... I use to run
across that now and then.... Parts soldered to the old leads on top of
the pc board as well..... Lotsa crazy stuff out there.....

Get some solder wick and remove the end of that one with the green crud on
the leads and see if there is a buncha wire still left on that tube socket.....
If it was cut, and not removed with a soldering iron, then the little wire
is still there.....

Do the other parts look like they easily went somewhere....?
Well then they did it more than once.....


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The component with the green crud on the leads appears to be a large wattage porcelain resistor. I never saw a capacitor that corroded like that. Maybe the pot is partially open and someone subbed the resistor for it.

I couldn't tell what it was.... Yah I never did see a cap look like that either.... They could
have done anything, and the circuit could have been changed too....
Even on a different computer I can't tell what that part is....

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It's a ceramic 30K resistor, wattage unknown. There are 4 other similar ceramic resistors in this set, all with this same type of odd corrosion on the leads.

That's a good idea about melting the solder and checking for loose wire ends. From the length of the cap, there's only 3 or 4 places it could attach. I'll give it a go :)

Squirrel boy gets my Genius of the Day award for this one! Used my solder sucker on every point that this cap could go to, and sure enough, found it!!! Thanks for the tip!!!

And now, on to the rest :)

Still there's the possibility that it was put there by some hack, along with that 30k ceramic resistor. I'd trace the connections in the vert lin circuit against the schematic and see if anything makes sense. That 30k is a long way out from the 470 in series with the pot shown on the schematic.

Where did it go to? is it C-63?

jr

Edit add: Is the 30K resistor *marked* as 30k or could it actually be the 470ohm resistor that has changed value?

I think it's a wire wound resistor. That's one crazy value change!
Neither schematic shows the wattage. Emerson seemed to use that type of high wattage resistors and on most, the leads corroded like that.
One the Sams, they show a -165 volt bias line.
BTW, what volume Riders is the Emerson sourced schematic in? Maybe, there's a production change bulletin, showing the circuit changes. :scratch2:

No, it's actually marked 30K.....I didn't test it.

Whoever was working on this set last must have either had no idea what he was doing, got frustrated and quit, or discovered something bad and said "the hell with it". I'm hoping it's not the latter. I found and traced all of the disconnected caps, which coincidentally were all in one row between the 2nd sync amp and the vertical output.

Not shown in the schematic that I have for what appears to be the same (or similar) set (PF set 126-folder 5) nor as an indicated substitution/modification... where does the other end connect?

jr

The 19AP4C was aluminized.

I have never seen a metal cone crt, that was aluminized.
The "C" probably only designates an improved or latest version. :scratch2:

I was just looking at the schematic again. In the picture, the vertical linearity pot is a rather high wattage type. The 470 ohm resistor seems to make sense, even if the pot is turned to minimum resistance, there is still bias on the cathode. I also notice the 6K6 is triode connected. I would restore the circuit to original, per the schematic.
I find it strange, that some of the vertical circuitry is so far away from the sweep tubes. Rather complicated set to work on, plus the wiring is like a rat's nest. :D

Aluminized 19AP4?
For what it is worth, my old GE tube manual shows the following for the 19AP4:
19AP4; clear glass, single magnet ion trap.
19AP4A; gray glass, single magnet ion trap.
19AP4B; gray frosted glass, single magnet ion trap.
19AP4C; gray glass, aluminized, single magnet ion trap.
19AP4D; clear frosted glass, single magnet ion trap.
I bet that some were also rebuilt with straight guns, as well.

Poor/complicated layout?
To me, it really looks like a "factory kludge"... The chassis still has the punch outs for the (5) 25Z6 rectifier tubes used in the 10 inch models plus other unused punch outs. :scratch2:

jr

I've never seen an aluminzed one either, but the Tung Sol data sheet does say
19AP4C - Grey Filter Faceplate Aluminized Screen

http://frank.pocnet.net/sheets/127/1/19AP4.pdf

For what it's worth, I had a necked 24AP4A that had an aluminized screen, so at least some metal cone tubes were being aluminized either by the manufacturers or the rebuilders.

Aluminized 24AP4?
For what it is worth, my old GE tube manual shows the following for the 24AP4:
24AP4; gray glass, single magnet ion trap.
24AP4A; gray glass, aluminized, single magnet ion trap.

I doubt that rebuilders normally aluminized or even redeposited screens, anybody know of one that did? :scratch2:

jr

RACS in France was still aluminumizing and phosphoring until they closed. Hawkeye was doing it in the early days when Scotty's father was still running the company. After the move to the final location that Scotty ran, they no longer did either process. At the new location all they did was re-gun the tube.

Short of breaking one open and checking how would you know if a metal cone tube was Aluminized?

You can tell on a glass tube because you can see it from the back side, no such luck on a metal tube.

For the moment, I'm going to assume that the last guy who had this set knew something about the components that I don't, and replaced some stuff or something that required the caps and resistors that don't show up in the schematic. I mean, you usually don't throw what looks like expensive high-wattage resistors into a set without a good reason, right?

You're right though, the wiring is kind of like a rat's nest, but I've dealt with a lot worse. My plan at the moment is just to finish up recapping, and see where we're at. After I got everything hooked up that wasn't, and got a lot of the caps in, I pulled the 5U4 and bench tested the chassis to see if the transformer was good. Ran nice and cool and all the tubes lit, so that's a good sign.

With an image on the screen, you can tell by looking down the neck of the tube. On tubes that weren't aluminized, you will be able to see the screen image reflecting off the gun assembly. At just the right angle, you can usually see all the way to the screen.

Clinton electronics did. Each of their rebuilds went through the oven 3 times.
They were North of Rockford, IL.

The early chassis, you're referring to, used in the 10" model with the 25Z6's was a totally different layout.
This chassis was used in the slightly newer models, with CRT's from 10" to 19", some with AM-FM radios. The front right corner, looking from the rear, had all kinds of knockouts for the radio IF transformers and tubes. It was cheaper to use the the same tooling, than to make up new.