Next step was to mount the yoke, so I got a piece of wood and cut out a hole into it and added a slice of cutting mat to hold the tube in nice and firm and I screwed the wood onto the hinge I previously used to hold the RCA vidicon yoke.
Now it's time to put the tube back in and fire it up and see if I get better pictures! The tube fitted into the yoke with too much play room so I added a piece of cardboard paper around the neck so it fits a little more snug. To hold the tube bulb end onto it's cushioned seating I simply used a few pieces of blu-tack. Now it's time to fire the camera up again and see what happens! Powering it up I got a much more straighter picture and can see the bottom of the scan area which is great! The problem however is the picture is too wide after I adjust the width to minimum so the width needs attention. Also vertically the picture is off centre too. Nonetheless the yoke works and I'm getting pictures and I'm happy with that! :D Here below are some videos from the camera with its proper yoke along with a video log:
The last two videos I edited in Pinnacle Studio 15 which I adjusted the width/height and positioning so the pictures look proportional, from that I noticed the width of the video is quite skinny so I reckon the beam is scanning a narrow area horizontally, so I think maybe not enough current is going to the horizontal coils to scan the full width of the Iconoscope's mosaic, so modifications are now needed for the deflection board to widen the scan area.
So that's my updates for now. A lot more work is needed on my camera to improve the pictures, so the next steps of modification will be modifying the deflection board as mentioned above, adding blanking to the tube to cut off the retrace lines and I need to somehow connect the video board closer to the tube so less noise is picked up on the target lead. So stay tuned for the next update when I work on those.
Since my last update I have made ENORMOUS progress with my Iconoscope camera to the point the pictures are very watchable, nearly noise free and nicely contrasted and picture frame being well proportional and I am now taking the camera on remote location for filming! So here's what I've worked on since my last update:
Firstly I decided to put the original larger lens back into the camera as from what I seen more light passes through to the tube than on the smaller lens and in turn the pictures might come out more contrastier. So putting the original lens back in it did improve the picture but only to a small extent.
Next thing I felt compelled to try for better pictures is bias lighting as I know bias lighting was used in Iconoscope cameras to improve the tube's sensitivity resulting in more contrastier pictures. So I shined my LED lamp and incandescent lamp around and behind the tube and I noticed it briefly made the picture more contrastier then went back to normal. I thought would that be caused by the "automatic level control" section on the video circuit? So I wondered what will happen if I were to disable the ALC circuit so I cut the connections of that circuit and fired up the camera and the picture became unstable shrinking down to nothing until I adjust the grid 1 voltage on tube which brought the picture back then the picture once again gradually shinks to nothing, very interesting effect!
So cutting the ALC wasn't gonna solve the issue so next I wondered what if I were to include DC target voltage as target voltage was used with vidicons and this circuit initially had target volts adjustment. For the Iconoscope I connected the target volts connection to ground. So I then decided to make an adustable target voltage adjustment circuit and connected it to the target volts connection on the video board. I fired up the camera and adjusted the target volts and it had no effect whatsoever!
So including target volts was doing jack diddly squat so I removed the circuit and connected the target volts connection back to ground again.
Next I decided to investigate on how I can widen the beam's scan area across the tube's image plate. Richard said more current was needed to drive the horizontal coils so I thought I'd try lowering the resistance in the horizontal drive circuit by shorting out the 270 ohm resistor between the 15V rail and the width adjust trimpot and see what happens. I fired up the camera and to my delight, the beam is scanning right across the width of the tube's plate! There was one problem though the little trimpot was smoking from too much current!!!
Obviously I needed a more heavy duty pot and higher wattage resistor so I replaced the trimpot with a larget 1K pot with a 1W 100 ohm resister in parallel which works out to be about 90 ohms and I placed a 47 ohm 2W resistor in parallel with the 270 ohm 1W resistor which works out to be about 40 ohms in resistance. Firing the camera up again, the resistors and pot didn't burn up and the beam now scans the full width of the tube's plate and in turn the picture is so much clearer and more contrastier yaaaaaaaay!!! :D
As the picture is off centred I decided to leave the horizontal/width adjustments to overscan so I can see the whole area of the tube and the complete picture. Now that I can see the whole tube plate I now see the picture is trapezoidal in shape known as keystone distortion, this is due to the beam scanning the plate on a slant which the beam has to travel further to scan the top of the plate than the bottom, hence the beam scans a narrower area of the top of the plate than the bottom. So will need to at some point incorporate a keystone correction circuit. Anyhow now my camera is making better pictures here are some videos I made:
The rest of the recent videos can be seen via these links:
Now that the pictures are looking so much better, next step is to straighten the picture up as it's rotated by about 5-10 degrees. So I rotated the tube's yoke a bit and rotated the tube till it looked straight.
Next I thought I'd play around with bright indoor lighting for the camera as I recently acquired some super bright 500W globes and a Hanimex Bar Light from a garage sale, so I lit my subjects up with the 500W light and they appeared better on the camera! One problem I found though is the globe was making my facial skin and eyes feel sore and burning even though I wasn't in front of it, I was told it was because these globes emit a lot of infrared radiation so will have to find a way to shield the infrared rays when using it.
Using the 500W light, here's some indoor videos made with it:
And below are some photos of the bar light and my subjects used to display on Iconoscope:
Next tangible thing to work on with my camera is noise shielding and reduction. I've seen in old pictures wire being wrapped around the tube's bulb and also foil wrapped around the tube's bulb so I got some wrapping foil and wrapped it around the tube and connected it to the camera chassis via gator clip and wire and this worked nicely in reducing picture noise! :)
Okay now that the picture is now much less noisy, it's time to make it even less noisy by shortening the target lead from target connection on tube to video board's preamp input. So I removed the video board from the left side and positioned it to the right side which is much closer to the tube's target connection and I shortened the target lead as much as possible. Firing up the camera again, I was very pleased to see the picture is now nearly noise free!!! :D