Early 50's set, Is this missing the deflection yoke?
 

I am considering buying this set, and this maybe an obvious question,
but is this missing it's deflection yoke?
I see something inside a box on the chassis that looks like a yoke, I just don't know. Looks like an early 50's set.

Magnavox300

isnt that the yoke on the neck of the CRT with the wire going to the HV box?

Weird lookin but i think its a yoke :D

SR

I see a yoke!

Looks like a WEIRD anorexic yoke, but can't think of any other item that would be on a b/w set's CRT neck. I would have suspected the yoke missing too, but does look like you have at least three wires going to it from what I can discern.

Ok, my fault.
I guess I am used to seeing the yokes with exposed copper pushed up against the CRT. In the photo, the yoke looked like a continuance of the CRT.

Deffinately not what I am used to seeing either. Don't blame you one bit for wondering. I would have REALLY wondered if I saw that just through the cabinet. This is not by chance what "electrostatic" looks like (as opposed to the usual magnetic deflection)??

I have never seen electrostatic deflection in person....so just curious.

Electrostatic deflection is done inside the neck of the tube with charged plates. The tube looks similar to a magnetically deflected tube but with a larger neck size than would be expected for a small tube and the lack of any yoke. Look up a 7JP4 for a great example.

I just wondered if there was an "external" type of electrostatic. I have seen just the theoretical drawings of it before....and aware that "usually" it's a set of charged plates inside the CRT for X and Y I guess. I did once see the CRT to one of Clive Sinclair's little mini set that reminded me of my little "TR" panasonics. The Sinclair had a "real fat neck" that was nearly if not as big as the screen. This was a real miniature one though. The little Panasonics are magnetic, with cute little yokes on VERY cute little CRTs :-P

After looking at the pic even more....YEAH....looks like a real thick neck, and then an odd termination and smaller neck. I was sorta being curious about those three wires coming from the cage to what LOOKED like that area. I'm not sure I have ever seen "three wires" to a yoke...but hey.....I was thinking "who knows..maybe vertical and horizontal with a common ground"

Here is a picture of my 1953 17" Philco... The yoke is seen ahead of the focus magnet, touching the bell of the CRT, but has no exposed windings wrapping over the bell. This is typical of 70 degree or smaller angle yokes of the period.

http://www.videokarma.org/attachment...2&d=1280082462

jr

It looks like a Sylvania to me, not a Magnavox. Higher end, 1953 model.

That is one nice '53 Philco. I like the field coil speaker and the UHF tuner kit.

Thank you! It was my in-laws first TV!

jr

yea its just a different shape

Different yokes for different folks!

That looks a lot like the inside of my beloved 1956 21" Philco. The Philcos were remarkably well engineered and well built, yet very simple. I can yank the chassis out of mine in a matter of minutes, but then again I have owned it since I was 13. Now I'm 43! I think the set might outlive me! It might even need restoration AFTER I do!!! LOL

The piece with the long bolt stickiing out is the permanent magnet focus unit.
Between it and the bell of the CRT is the yoke, with wires running from it to the HV cage. Hope you get it and make it worka again. Good Luck,
Cliff

Love the dueling 5U4s atop the PT.

Me, too. I've never had a TV with them in the PT, until I got my RCA roundie CTC-7.

I want to see more pictures of the OP's set!

I have some Hoffman Mark V chassis sets with 1 5u4 mounted on the transformer, but not 2! I also have a 1937 Philco Radio with the rectifier mounted on the PT.

What is that long thin copper colored thin coil going from the yoke to the socket of the CRT? Looks like a super long warped screw.

That's a flexible shaft to adjust the focus. They did it, so you didn't have to remove the back. There should be a hole in the back where it protrudes.
Made of the same material as the old speedometer shafts.:yes:

The Hoffman UHF models had 2 5U4's mounted the same way.
Also, the larger screen sets, where the B+ demands were higher.

I know that two 5U4 tube rectifiers represent a four diode smoothing of the AC waveform. I wonder if the old sets more commonly used plain full wave, full wave bridge, or perhaps even doublers. Maybe a little of all of them. Just curious.:scratch2:

Interesting that it has an Electromagnetic Speaker instead of a PM, 53 seems awfully late for that.

I have a 53 but the speaker is located in the bottom so I don't think I've ever looked at it all that closely, don't know what it is.

Those Cotton Straps holding the Yoke get very brittle, I broke one of mine when I changed the CRT just by bending it sideways, snapped off like it was made of Pasta.

I just checked my 17 inch 1953 console... the 4 wires going to the speaker (10" or so) look exactly the same, but the speaker has a choke mounted to the frame. The UHF tuner is hardwired to the chassis on the console, while in the table model the power for the UHF is taken from an adapter plugged in to the audio output socket (with the tube plugged in on top of the adapter). Both sets are early production '53 models, and were purchased before Christmas 1952.

Thanks for the "heads up" on the weak straps! I will be careful If I ever have to mess with them.

jr

That is the adjuster for the permanent magnet focus assembly. The field is adjusted by sliding a "shunt" in or out, the flex adjuster (which normally sticks out of the back of the TV) turns a screw, which slides the "shunt".

jr

You'd have to look at the schematic to see how they're connected. Sometimes in parallel, or each one connected, half wave. They also used two rectifiers using two high voltage windings to obtain two different voltage sources.