My B&W Iconoscope TV camera project

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Postby aussie_bloke » Tue Jun 18, 2013 1:20 pm

G'day all, just a little update on my Iconoscope camera.

As I have trouble getting a hold of a wide area photographic camera lens, I've decided to try making my own lens from 2 magnifying glasses, so I've done a little test tacking 2 magnifying glasses (both roughly about 9cm diameter) to a plank of wood and projecting the front yard onto a piece of paper with the size of the Iconoscope's mosaic drawn on it and it worked! :D I have a nicely projected 9cmx9cm picture on the piece of paper which is more than enough area to cover the mosaic! So now I'm gonna buy me a couple of magnifying glasses from my local el cheapo shop and some tube/container to fit them in and mount them onto a rackable platform to make my lens system.

Anyways that's the latest on my project, am still digging for info and questioning people and writing down notes for constructing the electronics for the camera as I know very little in designing circuits from scratch.
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Postby Harry Dalek » Tue Jun 18, 2013 6:21 pm

You might be able to house the lens in large PVC pipe cut to size they come in many sizes so you might be lucky for a good fit ? I can see Troy off to the hard ware store .

Are you going to make the circuits with modern day electronics as it might just be much easier to use valves and copy the old designs might speed things up ...there must be a few circuits out there for it ?

I am not sure if you have valves but ?
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Postby aussie_bloke » Tue Jun 18, 2013 8:28 pm

harry dalek wrote:You might be able to house the lens in large PVC pipe cut to size they come in many sizes so you might be lucky for a good fit ? I can see Troy off to the hard ware store .

Are you going to make the circuits with modern day electronics as it might just be much easier to use valves and copy the old designs might speed things up ...there must be a few circuits out there for it ?

I am not sure if you have valves but ?


I'm definitely going solid state with this project and have gotten some clues and a power supply circuit to work with so far along with some coil data. For the head amp I need a schematic from a 1970s 3x plumbicon tube colour camera head amp as they are choice for a head amp for the Iconoscope camera.

Anyways made further progress today with the taking lens, I have bought a couple of cheap $2 magnifying glasses from an el cheapo store and have tried them and they work good but then I thought add a third magnifying glass to see what it can do with projecting an image and I found that it made the image a bit smaller but intensified the amount of light being projected to the paper surface and the reduced size still exceeds the surface area of the Iconoscope's photosensitive mosaic plate, so three magnifying glasses was the way to go. Anyways I cut the handles off the magnifying glasses and I cut a piece of cardboard tubing to hold the magnifying glasses which I resized to fit them in and I glued them all in the tubing and the lens itself is now done and dusted and working great! :D Next step is to mount the lens on a rackable platform and house it inside the computer tower case enclosure. It has been suggested I devise some sort of iris system, from my knowledge of Iconoscope cameras they didn't use irises at the time as they needed as much light as possible due to poor sensitivity so for now I won't bother implementing an iris until the camera works and one is needed. Anyways here below are pics of the completed lens:
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Postby aussie_bloke » Wed Jun 19, 2013 2:22 pm

Done some further work on the lens system for the camera. Have found a suitable railing piece that will allow me to slide the lens back and forth which is the an aluminum front panel of an audio amplifier I scrapped, the lens slides nicely on it.

Some bad news with the lens however, after gluing the lenses inside the tubing condensation formed on the inside making the lenses foggy giving a hazy focused image, the weather has been cold and rainy so that would be part the cause but also possibly the glue I used might have had some vapour effect too though not sure. Will have to take the lenses out and wipe them and remake the lens system so they are easily removable when this happens.

Anyways having the lens on the inside of the PC case disk drive carriage sitting on rails, I found I had to move the lens too far close to the tube to focus distant images to the tube so will have to rearrange the lenses to lengthen the focal distance between the tube's mosaic and the back lens, I think spacing the lenses apart helps lengthen the focal point though will have to test again to be sure.

So here are some pics of the lens sitting on rails inside the camera's enclosure focusing an image onto the paper target:
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lens4.jpg
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Postby AncientBrit » Wed Jun 19, 2013 5:34 pm

re condensation I wonder if the plastic tubing needs venting between the elements?

Say a 1mm hole in the wall of the tubing between the lenses.

Cheers,

Graham
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Postby Klaas Robers » Thu Jun 20, 2013 6:20 pm

I don't understand why you placed three magnifying glasses in row. Then you get a focus distance that is too short to my ideas. The result will be that the aspect effects on a TV are bad.

In principle a camera should have the same opening arc as the viewers eye when watching the TV. For TV this arc is choosen to be 10 degrees in the vertical direction. Then the TV lines become just invisible.

This implies that the viewer should sit at 5.7 x the picture height from his screen. This also implies that the taking lens should be 5.7 x the height of the camera target. So the focal distance should be the same. I have the impression that one of your magnifying glasses fulfills this criterium almost, may be it is already somewhat too close to the target.

An extra advantage is that due to the smaller viewing arc, optical errors in your lens are less prominent visible, so you get a sharper picture. And then darken the space between the lens and your screen and look at the frosted transparent screen from the back side.

Succes.
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Postby aussie_bloke » Thu Jun 20, 2013 10:09 pm

Klaas Robers wrote:I don't understand why you placed three magnifying glasses in row. Then you get a focus distance that is too short to my ideas. The result will be that the aspect effects on a TV are bad.

In principle a camera should have the same opening arc as the viewers eye when watching the TV. For TV this arc is choosen to be 10 degrees in the vertical direction. Then the TV lines become just invisible.

This implies that the viewer should sit at 5.7 x the picture height from his screen. This also implies that the taking lens should be 5.7 x the height of the camera target. So the focal distance should be the same. I have the impression that one of your magnifying glasses fulfills this criterium almost, may be it is already somewhat too close to the target.

An extra advantage is that due to the smaller viewing arc, optical errors in your lens are less prominent visible, so you get a sharper picture. And then darken the space between the lens and your screen and look at the frosted transparent screen from the back side.

Succes.


Thanks for the info Klaas.

The reason for three lenses is because I don't know enough about optics to make the right kind of lens and so I experiment around with what I have available and see what brings about good results and the image focused from three lenses looked good at the time but found the focal distance to be too short as you stated.

Anyhow I have now rebuilt the camera lens which I've decided to use two lenses and it no longer fogs up inside and the focal distance is good enough to hit the Iconoscope's mosaic with the lens positioned up to 15cm away which is good by me. I have brought out the Iconoscope tube and projected an image onto its photosensitive plate and it looks quite good. I have attached below some pics of the new lens and the image projected inside the camera enclosure and on the Iconoscope itself.

I have looked at some Iconoscope cameras and notice their lenses are smaller in size and I notice when I use a single magnifying glass and project an image onto paper, on focusing it comes up quite large, so I will be looking into other options of lensing for the camera, but I think the lens I made will do the job provided of course the image projected is intense enough for Iconoscope's photosensitive mosaic to respond. I will have to read up more on optics as I haven't studied it enough to know the best lenses to make.
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Postby aussie_bloke » Sat Jun 22, 2013 7:09 pm

Okay, I have now riveted the lens railing to the inside of the disk drive carriage of the tower case and have nailed/glued the lens to a platform which slides in under the railing which keeps the lens secure and connecting a car oil dipstick to the platform I can slide the lens back and forth. So the rackable lens system is pretty much complete and working well and I can get a focus range from 55cm to infinite distance away from the lens. I have attached below some pics of the completed rack lens system.

I understand the two magnifying glass lens isn't an ideal for the camera due to the fact the projected image is much larger than the area of the mosaic on good focus which lessens the viewing area and also with the image spread over a larger area the image is dimmer than it would be concentrated on a smaller area. But it will do for now until I get the camera completed and test it out. I will of course look into building a more efficient lens or buy one of Ebay.

In other news of the Iconoscope camera, I now have schematics for a plumbicon camera head amp which is ideal for an Iconoscope head amp, found a service manual for a Philips/Norelco LDH1 complete with schematics at http://www.tvcameramuseum.org/norelco/l ... knotes.htm .

So things are really starting to come together with this camera! :D
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racklens4.jpg
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Postby aussie_bloke » Sun Jun 30, 2013 11:42 am

G'day all.

I have put all the updates of my Iconoscope camera on my website http://troysvintagevideo.0catch.com/ on my Iconoscope project section which now is in two pages:
http://troysvintagevideo.0catch.com/ico ... oject.html
http://troysvintagevideo.0catch.com/ico ... ject2.html
As I was developing the lens I made some video logs of the construction which are on the site. I have also added a sketch of the yoke construction with the data I have, am still missing info particularly the wire SWG gauges.

Anyways I hope to soon get started on constructing the head amp from the plumbicon camera head amp schematics I've recently gotten a hold of.
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Postby Steve_McVoy » Thu Nov 07, 2013 8:48 am

Very nice work.

I have worked with the 1846 in the 1942 military camera it was originally used in:

http://www.earlytelevision.org/rca_airb ... amera.html

Unfortunately, these tubes are very often gassy, so good luck with yours.

One other point. You will need to build your line deflection circuit with a trapezoidal signal at the frame rate to make the scanning illuminate the ike target properly. You can see how it was done in the original camera in the schematic diagram in this article:

http://www.earlytelevision.org/pdf/cq_5-57.pdf

Good luck with your project.
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Postby aussie_bloke » Wed Nov 13, 2013 10:38 am

Steve_McVoy wrote:Very nice work.

I have worked with the 1846 in the 1942 military camera it was originally used in:

http://www.earlytelevision.org/rca_airb ... amera.html

Unfortunately, these tubes are very often gassy, so good luck with yours.

One other point. You will need to build your line deflection circuit with a trapezoidal signal at the frame rate to make the scanning illuminate the ike target properly. You can see how it was done in the original camera in the schematic diagram in this article:

http://www.earlytelevision.org/pdf/cq_5-57.pdf

Good luck with your project.


Thank you Steve for the good words and the great resource links.

I have since progressed a bit further with this project though am yet to post the updates on my site. I have since progressed on the power supply side of things, put together a high tension 1KV power supply, I was given a -1KV DC power supply and I built the +/-12V power supply to drive it also connected a centre tap transformer, bit of overkill but got the -1KV output. Also I have built the head amp from a preamp schematic for a Norelco/Philips LDH1 http://www.tvcameramuseum.org/norelco/l ... knotes.htm the preamp is however oscillating very badly, probably due to ground loops or something, I don't know. My mate Richard Diehl of Labguysworld has kindly been helping me with this project with knowledge and resources so I owe much thanks to him.

Anyhow will post pics here of my latest progress soon but in the meantime I have uploaded some vlogs on my latest progress:
http://www.youtube.com/watch?v=gJqFxTd4FWw
http://www.youtube.com/watch?v=UF63Qek-a98
http://www.youtube.com/watch?v=kUPKmebVs6g
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Re: My B&W Iconoscope TV camera project

Postby aussie_bloke » Thu Nov 20, 2014 10:26 pm

G'day all. It's been a year since I last posted here on my Iconoscope project but I have been doing a lot of work on it on and off in that time period and thought I'd update you all on my progress. To talk about it all would become an essay so I will provide my website pages of my construction logs and just talk about the key points. The construction logs can be seen over these four pages:
http://troysvintagevideo.0catch.com/ico ... oject.html
http://troysvintagevideo.0catch.com/ico ... ject2.html
http://troysvintagevideo.0catch.com/ico ... ject3.html
http://troysvintagevideo.0catch.com/ico ... ject4.html

I have been corresponding with Richard Diehl of Labguysworld http://www.labguysworld.com/ via email and he has been helping me a lot with my project and giving me plenty of ideas which has made it more possible for me to further construct this camera. Richard suggested I first not worry about the keystone correction yet but first get the tube to output a picture before proceeding to the correction circuitry. He suggested for testing purposes use a 1 inch vidicon yoke for the Iconoscope tube, I so happen to have three RCA 30mm plumbicon tube yokes so I've decided to use one of those, I stripped the preamp off it and paired up all the leads, have worked out the horizontal coils but yet to be sure about the vertical coils. I also added cushioning and layers of cardboard paper to make the tube fit in nice and snug. For video amplification and deflection, I've decided to use the the video and deflection boards from my homemade vidicon camera for the task, this unfortunately meant I had to dismantle that camera but I can always reassemble it again if I chose to. For the preamp stage I constructed a plumbicon tube preamp circuit pretty much to the tee and it's working. Richard helped me with the high tension power supply section kindly providing me a -1KV power supply unit and a schematic for the voltage divider, so that's all constructed and working good. Due to the position of the yoke and the tube I had to redesign the optics replacing the original big 2x lens assembly with a single smaller magnifying glass lens. I have assembled all the power supply circuitry and they are all operational and they are now bolted down inside the enclosure, have mapped out where the video and deflection boards are going as well. So those are the key points of construction since I last posted here. I hope to get this camera completed enough for testing within the next couple of months and should it at all work I should get a trapezoidal distorted looking picture. Then from there I will look into keystone correction circuitry.

Anyways here are some pics of my construction progress:
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Re: My B&W Iconoscope TV camera project

Postby aussie_bloke » Wed Feb 04, 2015 5:15 pm

G'day all.

I've have been working hard on my Iconoscope camera project since my last update and the camera is literally nearly ready for testing. All of the latest construction log details along with pictures and videos can be seen on this page http://troysvintagevideo.0catch.com/ico ... ject4.html . In short since my last update I have tested out the video/deflection circuits to make sure they still work and they work nicely, have adapted the preamp to the video board and am getting a signal out when touching the input pin, I have added a back panel to mount the input/outputs and controls and switches, and cable tied all the wiring and secured the circuits. It was suggested for the Iconoscope tube I rejuvenate the tube by powering the tube heater to 3V for 2 hours and 5V for an hour so I did that as well. Now just need to do a few more things and it will be ready for the big test which should hopefully be within the next few days!
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Re: My B&W Iconoscope TV camera project

Postby aussie_bloke » Sat Feb 07, 2015 9:29 am

G'day all.

I have completed the camera to testing stage and have finally fired it up! There is good news and bad news. Starting with the bad news which is just simply I haven't got a picture yet, the good news is I am getting a light response on the TV screen when I shine my LED torch across the lens on the Iconoscope tube's mosaic which a bit of light plumes out from the left side of the screen, plus when I adjust the grid 1 and anode 1 voltages I get some activity on the TV screen. So it is quite possible this tube is fully functional if connected to its correct deflection yoke and circuitry to drive it!

I can think of various reasons why I'm not yet getting a picture, the biggest reason would lie within the deflection yoke and the deflection circuits. The yoke was meant for a 30mm plumbicon or vidicon tube used in a telecine machine and is quite long and I think the horizontal/vertical deflection coils are likely in the incorrect position over the Iconoscope tube so hence the beam isn't getting deflected properly, I think that would be the primary reason why it isn't working properly. Then there's the guesswork factor of which set of wires connect to which set of coils on the yoke as there's several, I checked the resistances of each pair and picking the horizontal is easy as it's of the lowest resistance, the vertical was harder as there's one pair of wires around 50 something ohms and the other around 100 something ohms, I ended up testing each pair and found the 50 something ohm pair gave the best response from the tube so it's probably the vertical coils. Then of course is the peak to peak voltage levels of the horizontal/vertical outputs of the deflection board, I am getting about 40V p-p out from the horizontal and 4V p-p out from the vertical, in the original 1846 Iconoscope bomber cam circuit the voltage required out is 625V p-p horizontal and 68V p-p vertical, having said that the yoke I'm using I assume would likely require much lower voltages as in the 70s power efficiency in design of cameras was much better than in the 40s. Anyways these are thoughts from the top of my head, I could be right, I could be wrong.

Anyways I have made a couple of videos of my camera fired up and they are on YouTube:
https://www.youtube.com/watch?v=bu-sl5mZoDk
https://www.youtube.com/watch?v=1wCoF_KC5xw

I have decided to remove the tube to check to make sure it hasn't somehow gone to air, looked at the neck, no sign of whiteness around the getters, so far so good! :) I have put the tube back in it's padded box for now until I can work out what I will do next with the camera. I think I should start making me a deflection yoke as I've got the data on how to make one for an Iconoscope.
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Re: My B&W Iconoscope TV camera project

Postby Klaas Robers » Wed Feb 11, 2015 3:21 am

Have you ever thought of the idea that the pick up tube only can work in a somwhat proper way if you place it in total darkness? Now there is so much light falling on the mosaic plate that the picture is invisible in the stray light, It is like making photographs with a totally opened camera. The only light that should hit the tube is light coming through the lens.
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