This is my number one dream project, to build a homemade solid state 3 inch image orthicon tube B&W television camera. I first thought up building this project in early 2010 when I saw Paul Marshall's homemade solid state photicon/iconoscope tube B&W video camera which he built from scratch and seeing CQ-TV articles 89-91 on construction of a 4.5 inch solid state image orthicon camera, these projects and my love for vintage images from vintage tube cameras totally inspired me to build an image orthicon camera of my own. So I started gathering up as much data on vintage television cameras that I could muster and have since gotten a few image orthicon tubes along with an iconoscope and vidicons imported from USA, service manuals for a Marconi MK3 camera and with pure luck a Marconi MK3 camera chain, service manual for a couple of other image orthicon cameras such as a Dumont TA-124-A and TA-124-B and Visual MK10, books on the fundamentals of camera electronics, parts to build a yoke for the tubes and much more. I have also gotten in touch with camera engineers who are kindly assisting me with technical advice on building this camera. And of course I decided to test my abilities on camera construction by building a 2/3 inch vidicon camera from a schematic to prove to myself I am capable of building a camera and with much online help from my technical friends I got it to work and make good pictures!!! :D
So now it's time to really get started on building this 3 inch image orthicon camera! I have started off on the most challenging part of the project which is to build a yoke assembly for the tube as yokes seem to be extremely hard to get a hold of. I was fortunate to find out my contact George Usher whom I've known for a while use to work in amateur television broadcasting at ATV Adelaide and constructed image orthicon cameras so I have been exchanging emails with him on construction of the yoke for a 3 inch image orthicon tube and he has kindly provided me with enough info for me to get started. Another great source of info I have gotten a hold of is from CQ-TV magazine issue 33 from 1957 which has data on construction of a yoke for a 1 inch vidicon tube camera. So here below I present sketches from George and myself on construction of the yoke for a 3 inch image orthicon tube:
A couple of basic diagrams of the cross section of a 3" IO tube and it's yoke coil assembly
George Usher's cross sectional diagram of the horizontal and vertical coils and a diagram of the coils being wound around the bobbin
George Usher's sketches of how the coils will look wrapped around the tube along with a cross sectional diagram of the horizontal and vertical coils and a sketch of the coils wound around a bobbin. Below are a couple of my sketches of he focus and alignment coils
My sketches of the the focus coil and the horizontal and vertical coils and alignment coil wrapped around the image orthicon tube
My sketches of the annular base socket ring with the wires coming from it and electrostatic shielding around the tube in between the insulation that's between the horizontal and vertical coils
George Usher's diagram of the annual base socket ring
Lugs from valve sockets that can be used for the annular base socket ring
My sketch of the deflection coils wound around the bobbin with a suggested width of 15mm
My cross section sketch of the deflection coils wound around the bobbin with pins at the corners after each winding
My cross section sketches of the deflection coils wound around the bobbin. Now question is do I wind the layers up then up in the next winding then up again etc or do I wind up tot the top then down to the bottom and up and down etc.?
My two cardboard tubes which I will be using as formers for the focus coil (left) and deflection coils (right). The focus former fits the tube like a glove, the deflection former I had to cut and resize to make it fit the tube
Deflection former after resizing fits the tube very well with only 2mm clearance space
This is the first deflection former I cut to size, I cut it a little bit short so it just doesn't quite fit the tube
Here is an example of a totally transistorized solid state 3" image orthicon camera made in 1964 which is a Visual MK10, this is the American version of the French Thomson CSF CO 301 3" IO camera made in 1959. I posted this as I have all the schematics for it and am seriously thinking of basing my solid state 3" IO camera off this design. The biggest challenge though is finding suitable substitutes for those old transistors that are no longer available these days.
This is a rough sketch I made of an ideal enclosure for the 3" IO camera, I came up with this sketch from looking at a few cameras, it remotely looks like the 1974 Sony DXC-1200 colour camera.
So that's where I am up to so far with my solid state 3" IO camera project. I am still looking for more information, more parts and any online technical assistance so if anyone is interested in helping me with this project, you can contact me through my email address firstname.lastname@example.org