Yet Another Motorola VT-71 Restoration

[kvflyer]

This is my first attempt on a restoration of an Electrostatic Deflection TV. I remember Dad having one of these on the floor in the basement when I was a kid. I have his old Sams Photofact with voltage readings written in. That is what I used for this restoration. I got the set from the second owner, the son of the owner. Coming from eBay, I paid about $100 for it. So why so much? It was 100% complete with the knobs, bottom and back. The other VT-71 that I have is missing the back but has all of the knobs.


So as you know, the CRT, a 7JP4 is often bad. Over the years, I bought a spare from one of the members of this forum thinking that most likely, the set that I get will be bad. I have no way of testing the CRT.

So, lets get started. Here is the front of the cabinet.




I has the usual rotted picture tube surround. I had to carefully rock the CRT back and forth to free it. And, as you guys have said, that stuff just came off with water. I was so happy that it was that easy.

I have a new reproduction mask that I got from an ARF member. So, that issue is solved. As for the cabinet, it is in fair condition. I will concentrate on the electronics first and go for the case later. Maybe even in Florida when I move there.

Note: This thread is also running on another forum so if it looks familiar, well, you know why. I am further ahead than this appears so bear with me and I will catch this thread up to the original one for those who have not seen it.

[kvflyer]

Here is the top of the chassis. Nice and clean with a good copper plating. It should clean up very nicely.



And here it is underneath before I start.



More to follow!

[kvflyer]

As you know, the first thing to go is the electrolytic capacitors. Here is the first one, a two section after the lip has been pried up. This set has a voltage doubler power supply and a "Hot Chassis" so all of the capacitors have cardboard sleeves.



Here is how it looks close up prying up that lip.



And after you yank the guts out, this is what is left. Note the 62 year old rubber band. It was still elastic!



And here is what is now going inside of the aluminum can.





Almost ready to crimp the can back together. BTW, I tested each can before crimp. I didn't need any more surprises!



More to come...

[kvflyer]

Looks like an original doesn't it? Mind you, there are three of these caps and some pictures are of one cap and the other pictures are of one of the other caps. But you get the idea. After I did two of these I got to thinking, "Why did I remove the wafer? I had to drill out the rivets. And then, I had to use screws and nuts to put them back. I could have just removed the capacitor from the wafer. I got smart after the second one...

[kvflyer]

Here is an earlier picture that I didn't have time to upload yet. I will take close-up photos later and post them as well.

For all, these are about 1/2 of the capacitors replaced so far. All capacitors were carefully unsoldered and totally removed from the socket or lug. I left no pigtails behind. And, this time did not break a single lug!

[kvflyer]

And here you can see the 6,000 WVDC capacitor that an electrostatic set needs. These little guys are available from Dave of Just Radios in Canada. They are not expensive. A lot smaller than those huge wax condensers.

[kvflyer]

This Motorola VT-71. It is working but I have some traveling to do so I have to get back to it. As you can see, the usual deteriorated CRT surround. I have a new repro one so that problem will be resolved.




All caps except mica and disc have been replaced. What I found was any repairs done were done to the HV capacitors. ALL other components are original... or shall we say, "Were" original. Whomever did the repair work just snipped off the component and then tacked it back to the terminal. It made it easy to remove. But I got all traces of the old wire out of that little hole. Two mica capacitors were just tacked in. They measured perfect so they went back in the proper way.



Ad it actually now does work. First electrostatic set that I have worked on. I guess that an oscilloscope does not count!