Mystery chassis....??
 

Got this chassis as a present from DavGoodlin :)

He said it was an Admiral, but there's no way it's an Admiral. Take a gander and see what you think it is......

The only indication is a mark of Emerson on the ballast tube, but I can't find any Emerson sets that have this style control layout.

Look at all the filter cans!!! :eek: And a ballast tube and selenium rectifiers with a 12" screen. This is an odd duck, whatever it is.....

Emerson for sure...In the earlier 10" model the 5 holes at the rear of the chassis were populated with 25Z6 rectifiers.

jr

Pretty sure it is an EMERSON chassis Tim. Had one like it 35+ years ago. Pretty sure it is HOT--that tranny is only for filaments..

I have never seen the 12" model but this chassis likely came out of a combo like the 618 or 630.

http://ebid.s3.amazonaws.com/upload_...7-16520-24.jpg

edit add: earlier thread about a 10" model found in Denver:

http://www.videokarma.org/showthread.php?t=266947

jr

Could be an Emerson 571B, the 571A had the 25Z6 nightmare, the 571B had Seleniums IIRC.
Definitely Emerson though.

In any case it's an awful set to recap, just look at all those cans!

Edit, you said it has a 12" tube so not a 571.

http://www.vintagetvsets.com/images/emerson571.jpg

Well, either way.....it's getting stripped and hitting the curb unless someone needs parts off'n it. Testing the 12LP4, so we'll hope for the best there :)

I recently "did" an Emerson 698 14 inch from 1951, and it was a real PIA. One of the only things that saved it from being parted out was that the 14BP4 has excellent emission, and also it is a very clean set, inside and out. And it's small. The power supply circuitry is a nightmare, and I wonder about the EE's who designed it. Still has some fold over issues, but I'm done with it for now. Decent pic though, aside from the minor deflection issue. :yes:
Kevin

Emerson for sure I have a double d 10" that looks like that

I wondered back in 1980 or so...ans STILL do wonder today--seeing that picture again..why did they use SO MANY filter cans? Reminds me of the "locomotive chassis" that has a lot of caps --I think the 1st gen or so.. I understand the ened for a few caps for a doubler and filtering--but beyond that?

This Sams from the ETF site reveals that the set had *two* well filtered voltage doubler supplies, one positive and the other negative. Both the 25Z6 and selenium versions are shown..... lots of caps!

http://www.earlytelevision.org/pdf/E...Sams-76-11.pdf

jr

It probably is an Emerson set. I saw at least two Emerson branded tubes in the chassis.

I don't know where you saw that Emerson logo. I looked at the ballast tube and didn't see anything but a perforated cylinder over the tube itself; there was no logo on that cylinder, unless I was looking at the wrong part.

BTW, this is the first TV I've ever seen that uses a ballast tube in the power supply. Every set I've ever worked on has had a power transformer and at least one 5U4 rectifier, or series string filaments with seleniums.

That this set uses a ballast tube probably dates it to the late 1940s--'47 or '48. By 1950, however, I am sure the 5U4 had taken hold as the rectifier tube of choice in most TVs, although my folks' second set, a 1955 Crosley Super V 21" b&w console, still used selenium B+ rectifiers. That set had two such rectifiers, probably wired in parallel across the output of the B+ supply. The plate voltage for the tubes was probably taken directly from the output of the rectifiers and fed through at least one filter capacitor.

Transformer is only for filaments.. set is HOT.. pair of doublers for B+ and B-

Did you catch the error(s) on the 25Z6 supply in the Sams that I linked?

jr

The set, definately is an Emerson 1949, 12" chassis from a TV, radio, phono combination.
The first set, my parents bought was the TV only model, using that type chassis. A smaller type console, where the speaker was as large as the picture. The ballast was for surge limiting of the two power supplies.
The CRT went weak, when the set was about four years old. They gave it to me, to take it apart when I was about ten years old.
Regarding the Crosley set, that model used a voltage doubler, two seleniums and a voltage doubling cap, before the two rectifiers and two caps and a choke to furnish the B+ voltages. It also used the audio output tube as a voltage divider. I common scheme that many manufacturers used. :thmbsp:

I did not study it real closely...BUT I thought I saw a cap connected wrong--for a doubler--and perhaps a couple MORE backwards on the filter section?

I think so also... looks to me like all 3 of the electrolytics in the 25Z6 negative supply are backwards.

jr

Not the FIRST time I have seen that in a diagram. IIRC...the diagram for my 48-700 had one or more electros wired BACKWARDS..for the HV supply...

Don't they PROOFREAD these diagrams--before they are published ? I would expect TODAY...maybe not..but back THEN..when people took MUCH more pride in what they did..they would have triple-checked for errors..

The selenium rectifier circuit shown, seems to be drawn properly.
The power supply was the only repair that our set had in four years of use.
Emerson built a projector set, that used the same basic chassis, per Riders.

I stumbled across this old post, and wanted to add some information. The first Emerson TV was the 545, which had a power transformer. The cheaper 571 had the hot chassis, with all of those 25Z6 rectifier tubes. The incoming AC is doubled to about 250, and is also rectified to give a negative 125 volts or so. This gives about 375 volts end to end, to supply the deflection circuits. For the next production of that chassis type, Emerson replaced the tube rectifiers with seleniums.

I wanted to add this information, in case anyone here gets to work on one of those old beasts. I have owned an early 571 for 40+ years!

I have a 638 console that uses the same chassis with the selenium rectifiers. It also has all those open holes were the tube rectifiers were in the previous version. I also have the 14" 698 model that stromberg6 mentions. It's been a 4 or 5 year work in progress but I'm very close to firing it up. I've nicknamed that chassis the spaghetti monster. It's just a wiring nightmare. :D

I haven't run across a '40s Emerson that wasn't!!