all tube TV camera

Thanks ewrts for those good tips!
Sorry to be so long getting back to you but the forum either didn't notify me that you replied to this post or I missed the notice.
Ed Sharpe at the museum sent a closeup of the IF coil (it's not a transformer) that we can copy.
Been adapting DIPTRACE to make tube schematics and having some good results.

I built an all-tube TV camera many years ago as a science fair project. (It used a 7038 vidicon.)

Those peaking coils (in the video amplifier) are not particularly critical in value. Being off a little won't have much effect on the picture - it will just add a small peak or droop to the highest video frequencies. You probably won't notice much difference. I think that the 100uH and 50uH substitutes will work just fine, as long as their self-resonant frequency is higher than a few MHz (the coil manufacturers usually specify self-resonant frequency).

Unfortunately, I don't know what to recommend to replace the TV IF transformer. Possibly you could find an old tube-type TV and use one of its IF transformers.

One thing to remember when adjusting the camera controls is to keep the vidicon beam current (set by the grid 1 bias voltage) at the lowest value that produces a good picture. That will minimize the chances of writing a long-lasting raster image on the photosensitive surface of the vidicon, and also extend its useful life.

Be sure your horizontal and vertical deflection circuits are working properly before you install the vidicon. Lack of beam deflection will quickly burn a line (or a dot) in the photosensitive surface and ruin the vidicon permanently.

I have no experience in TVs but instead of physically changing the coils, maybe add a trimmer cap to adjust? You would have to know the desired frequency and calculate for needed cap size.

We are bound for Belize June 14 but the project is still moving along. We’ve acquired
most of the parts including a transistorized RCA surveillance camera containing the focus coils and matching vidicon we needed.
BTW, the vidicon Dave sent is an exact replacement for the Conar-800 camera plans we are using!)
The most important find was here:

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at the Southwest Museum of Engineering, Communications and Computation in Mesa AZ.
This camera from the 60’s was a kit designed for HAM TV.
Ed Sharpe, the director of the museum has been a tremendous help to us on this project!
However here is the problem,
The plan calls for five inductors that I’m stuck on, and perhaps somebody can help with some advice. Here are the remaining parts to find.
2 peaking coils (red dot)93uh
and
2 peaking coils (blue dot) 55uh

My question is, do these have to be 93uh and 55uh, or will 100uh and say, 50uh work?
Or how about pulling off the turns on a 100uh to reduce it to 93?

Then I’m fuzzy about this i-f coil. No part number is listed. We are trying to get a photo of the coil from the camera on display at the museum.

1 TV i-f coil (tuning slug with two leads)

So appreciate any help you all might have!
Phil

philledger wrote:

well, that didn't work because i must wait 7 days to post emails.

There is a reason for that. To stop spammers. Good luck on your project, you may have to visit some college libraries for older publications and books.

E-mail sent.

just take my user name and add:
@gmail.com

well, that didn't work because i must wait 7 days to post emails.

It's yours. PM your info & I'll send it to you. I know they're pretty expensive, but as I said, I don't know if it works. I don't have any use for it.
Dave

Thanks Dave, appreciate the offer. Don't think it will do me any good without the focus coils but would like to have it. That would be a start in the right direction. What would you have to have for it?
Phil

I have no idea if it still works, but I have a Vidicon 7735A tube just collecting dust if you need one.
Dave

Hi! My name is Phil.
I’m a missionary and tinkerer of 60+ years based in Ft. Myers FL. Remembering the days of real craftsmanship in electronics and always have had a fascination with vacuum stuff. Built my first tube project as a kid, a one tube capacity relay that used a 2D21. Years have passed and the bug is still there.
Photo conductive tubes are of special interest, especially camera tubes. Saw a couple of vidicons on the web awhile back and began thinking about what it would take to scratch build an all tube TV camera. My electronics theory is pretty full of cobwebs, but if you work through a project, at the end you know some things you didn’t know before.
Seemed pretty straight forward at first, just get a tube and add some video amps and a power supply. But there doesn’t seem to be much out there in the way of plans. Found some data sheets for 3 different tubes, a 6198, a 8134, and a 7038, with some example circuits in them. Have a Hewlett Packard 122AR scope in workin condition that could be sacrificed for the project.
Problem is finding an old camera with the focus coils intact without paying an arm and a leg for vintage antiques’! I thought a “one tube” B&W surveillance camera would work from the 70’s and just gut the solid state electronics. Even finding enough data to tell what’s in them old cameras is difficult.
Some old QST’s have extensive articles from the 50’sand 60’s on DIY ham TV but the sites I’ve checked want a fee to view the docs. So I thought I’d just drop in on you guys for some input of any kind.