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  #121  
Old 03-12-2019, 04:51 PM
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UPDATE, MARCH 12, 2019, DAY 224

THE SURGERY CONTINUES. From Mike:

“Greetings. The first “pass” at the high voltage cage is finished. I say “first pass” because the convergence pot issues are still experimental and I will likely need to make some component adjustments of the high voltage resistors that form the divider circuit on either side of the new pot in order to bring the convergence in to range. The reason for this is that the original pot is 60 megohm and the new circuit with the Zenith 63-7145 only has a swing range of 20 megohm. Some resistance is already built in to the Zenith part so that has to be considered in the calculations. I hope that convergence can be achieved within this new range. If not then I will be experimenting with the values a bit. The important thing that I need to adhere to is the original divided resistance value of the circuit since the 3 circuits (Focus, High Voltage Regulation, and Convergence) all interact a small amount by existence of these resistance values. The total value that I removed was between 230 and 240 megohms. My new value across the divided network is 219 megohms and there is a 7 megohm resistance built in to the new pot at the swing arm so that introduces some need for experimentation which I hope is soon to come. Also, I will soon need to address the issues with the crt socket. I have found a vendor but they are not responding to my queries about availability and cost. I may have to attempt a rebuild of the original socket.

Pict. #1 Old convergence pot left and Zenith 63-7145 right, mounted to the original bakelite panel with nylon screws and plates.
Pict. #2 The new circuit with experimental values shown.
Pict. #3 The original Focus pot which cleaned up nicely and seems to be OK. New wiring to the pot along with new capacitor (yellow) and High voltage 8 megohm resistor (blue) hard to see behind the cap.
Pict. #4 High Voltage cage with some, not all new wiring is complete. Note that the original 1AX2B focus rectifier tube is now solid state. (white stick near center). And the control shaft coupling to the new convergence pot was accomplished with a high quality piece of silcone rubber tubing. (lower right, orange) . And finally, all 3 of the H.V. rectifier tubes are replaced with a matched set of JAN Mil. spec 1B3’s.


Cheers, Mike”

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  #122  
Old 03-15-2019, 02:31 PM
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We have a heartbeat ...

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  #123  
Old 03-15-2019, 07:01 PM
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Quote:
Originally Posted by etype2 View Post
Cabinet looks nice, but what part of it is beating?
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  #124  
Old 03-17-2019, 10:20 AM
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Quote:
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Cabinet looks nice, but what part of it is beating?
He said the "heart".
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  #125  
Old 03-17-2019, 05:25 PM
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I've not seen any sign of a heart beat yet! A heart throb of a cabinet, yes.
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  #126  
Old 03-21-2019, 02:58 AM
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UPDATE, MARCH 21, 2019, DAY 233

From Mike: Here is the latest. I have received word from Steve McVoy at ETF that he has NOS sockets for 15GP22 crt’s. He is sending me one and only asking for a donation to ETF of $20.00. I sent him $25 as a donation and the socket should be here soon. The recent action on the restoration is that I installed a line fuse on the primary of the power transformer (where it belongs). The fuse is located on the top of the chassis next to the horizontal output tube sockets. The other progress is the new covers for the deflection yoke. I purchased 2 sheets of ABS plastic 1/16 inch thick to make the new covers.

Picture 1. The newly installed line fuse.
Picture 2. The ABS sheets.
Picture 3. The old yoke cover repair.
Picture 4. The old covers removed.
Picture 5. New ABS parts.
Pictures 6,7 New parts installed with nylon screws and spacers.

Cheers, Mike

https://visions4netjournal.com/westinghouse/

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Last edited by etype2; 03-21-2019 at 03:01 AM.
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  #127  
Old 03-21-2019, 02:12 PM
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Quote:
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Cabinet looks nice, but what part of it is beating?
We saw video signals on the scope. Can’t get into it more then that for now.

When we get the new socket, Mike will install it and the plan is still to try to jig this chassis to a 21FBP22 in order to finish the bench work and before installing the 15GP22. He will need to custom make the cables to connect the yoke and crt but most of that is worked out. This will allow Mike to check the voltages in the original electrostatic convergence circuits without actually connecting them to a crt. The picture will be small on the 21FB due to the different deflection angle of the yoke but the picture should be there. Mike is not sure how the different deflection angle is going to affect the angle of incidence through the aperture plate and on to the phosphors. It might not work at all. IF there is enough magnetism in the static convergence magnets of the 21FB, then the beams will bend where they need to in order to do the job since all we really care about is "rough" convergence for now. . It will be a fun experiment to say the least. Plan B is to jig it to a monochrome crt with the proper deflection angle and then patch in the signals (RGB) and Minus wye) "one at a time" to do testing.

Getting close.

Edit: Many thanks to the ETF. My donation sent.
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Last edited by etype2; 03-21-2019 at 06:52 PM. Reason: Typo
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  #128  
Old 03-21-2019, 08:05 PM
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Originally Posted by etype2 View Post
The picture will be small on the 21FB due to the different deflection angle of the yoke but the picture should be there. Mike is not sure how the different deflection angle is going to affect the angle of incidence through the aperture plate and on to the phosphors. It might not work at all. IF there is enough magnetism in the static convergence magnets of the 21FB, then the beams will bend where they need to in order to do the job since all we really care about is "rough" convergence for now. . It will be a fun experiment to say the least.
Deflection angle should only change scan size. The guns will still hit their intended phosphors (provided purity was/is set right). The phosphors are deposited using 3 photographic silk screens...Each photo is made by placing a light source where a gun is supposed to be (one is done for each gun position/phosphor color) and shining the light through the shadow mask (deltagun CRTs don't use no stinkin aperture plate! Patooey ). Thus the mask holes make the phosphor dots. The gun position light source hits the mask at every angle the yoke deflection should be capable of...Granted post deflection like a magnetized shadow mask, or pre-deflection like a mis-adjusted purtiy/static convergence magnet set up can drag the beam places the light source couldn't readily be...

Part of the reason the purity rings exist (besides the big ol celestial magnet we all live on) is to deal with manufacturing tolerance. After phosphering the screen the shadow mask had to be put back on the screen within a certain fraction of the place it was when the silk screen pictures were taken, that has to be mounted up to the bell of the CRT and the gun has to be placed within a certain tolerance from where the light source was...Every one of those placements had tolerance, and without the compensation of purity rings (or magnet) that tolerance would probably have been too tight to manufacture......When you think about it color CRT tech was somewhat of a miraculous achievement with the technology of the day.
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  #129  
Old 03-22-2019, 11:13 PM
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[QUOTE=Electronic M;3209603]Thus the mask holes make the phosphor dots.

Light source passes through mask holes unto the phosphor dots.
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  #130  
Old 04-07-2019, 05:18 AM
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APRIL 7, 2019, DAY 250

From Mike: Greetings. The socket has arrived from the Early Television Foundation. A real nice, high quality socket and a bag full of connector pins. So, I have to find the proper wires in order to complete that task. I could just use any wire and any color, but that is just not my way. The wires need to be the proper color and stripes for their function of the signals. It makes troubleshooting a lot easier in the event that it becomes necessary, and it retains the original equipment manufactured specifications.

I have assembled the new crt socket. It is ready to install.

Picture 1. The “kit”
Picture 2 and 3. The assembled socket with all new wires.

Cheers, Mike

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Last edited by etype2; 04-07-2019 at 05:25 AM. Reason: Typo
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  #131  
Old 04-08-2019, 08:54 AM
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Where in the heck did you find wire with stripe tracers on them? A hidden stash?
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  #132  
Old 04-08-2019, 02:46 PM
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Where in the heck did you find wire with stripe tracers on them? A hidden stash?
50 years of repair work. :-) The set is going on hiatus for the next month due to holiday.
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  #133  
Old 04-09-2019, 12:42 AM
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From Mike tonight: “Hi Marshall. I have mentioned in the past, several different ways that I might "jig" this chassis. My choice is now, to jig it to my usual 21FBP22. The picture will show up small in the center of the screen but that is something that is just "understood" because of the difference in the deflection angles of the sweep circuits. The purpose is to see an image and test the circuits. I recently mentioned too that I was not sure what the result would be with the "path" of the electrons on to the individual dots since the deflection angles are different between the 15G and the 21FB. My conclusion on that is, the guns in the crt are placed in such a way (angularly) to target the dots through the aperture mask. And since the crt face is spherical, then that should all be taken care of within the design of the tube being used. In this case the 21FB. The convergence on the 21FB is magnetic as compared to electrostatic on the 15G. So the only convergence that will be correct will be in the center of the screen, which, in my case, is fine for the testing purposes. I have spent this evening making the extension cables for the Westy yoke. The hookup to the jig for the crt will be completed tomorrow night. If all goes well, I might have an image on the screen tomorrow evening. This is going to be fun. And it may be a "first", as far as jigging a 15G chassis to a 21FB.


Cheers, and I wish Farsworth was still here to share in the experiment. I call this "empirical" testing.

Mike”

I’m itching to see video, be it as it may.
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  #134  
Old 04-10-2019, 02:23 AM
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UPDATE, APRIL 9, 2019, DAY 252

WE HAVE VIDEO! FIRST IMAGES.

From Mike: “Hi Marshall. The jigging process went as planned. The focus voltage is missing and I’m not sure why just yet. I ran out of time tonight. There is a LOT of GOOD NEWS though. The image is there. It is in good vertical and horizontal lock so the sync circuits are working and the chassis is actually sweeping a raster. With no focus voltage, the images are very blurry. I will sort that out when I return from my vacation. The other good news, is that the convergence voltage *(on the wire that is not connected to anything),* is swinging from 5 KV to 8 KV with the convergence pot. That means that I hit the numbers quite close with my calculations on the first pass. Very, very good news in my book. I am pleased with the results tonight even though there is an issue with the focus voltage that I did not expect. Also, I have not installed any purity correction yet and there is no static convergence installed yet. And, the images here are showing a “ring” in the foreground. That is the chassis portion that normally carries the deflection yoke. And there is no way to keep it out of the picture. All I wanted to do tonight is display an image. So here they are. Likely the first images that this set has displayed in many years. We are winning.

Regards, Mike”

** The wire from the convergence is ready to connect when I replace the crt socket which will happen after the jigging and before I install the 15G, and the pot is installed as per the picture I sent several weeks ago. And this part is still considered experimental until I find the correct voltage value for the 15G. The convergence wire will remain connected to nothing at this time, but will serve as a test point for voltage adjustment by the new convergence pot. When I am satisfied with the voltage numbers then I will do finish work around the pot and install a barrier insulation in the cage.**

Author: On day 252 of this restoration, we have our first images, albeit, very blurry. I feel good about this and it’s definitely a milestone in the restoration.

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Last edited by etype2; 04-10-2019 at 02:28 AM.
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  #135  
Old 04-25-2019, 06:37 AM
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UPDATE, APRIL 25, 2019, DAY 268

From Mike: “Greetings. Here are the first “in focus” monochrome images of the set when jigged to a 21FBP22 crt. This is a milestone in the restoration process. There has been a minor setback with the Vertical Convergence Transformer and it has been bypassed in order to allow proper focus voltage to the crt. This jigging process will now allow me to do troubleshooting on the chroma circuits. There is no sign of color bars or color at this point.

Picture #1 Crosshatch pattern through the yoke frame with many vacuum tubes lit up keeping me warm in the shop.
Picture #2 Crosshatch pattern closer. Only center convergence and purity settings are possible with the 21FBP22 tube.
Pictures 3,4,5. Images from a show on antenna TV.

Cheers, Mike”

Author: Definitely a milestone Mike. We now know the chassis circuits are working to produce a picture. The convergence transformer may be arching internally. We are working to resolve the problem.



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Last edited by etype2; 04-25-2019 at 04:26 PM.
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