I am building myself a B&W vidicon tube video camera as a fun project as my passion for old cameras has grown increasingly. This is a warmup project to get me familiar with camera technology for the image orthicon tube camera I plan to build later on. I have based this vidicon camera project from a vidicon camera schematic given in "Amateur Television Handbook" written by John L Wood and Trevor Brown. This camera is going to use a 2/3 inch vidicon tube that has electromagnetic deflection and focus, I have a few of these tubes so I'm all good with tubes. I have so far completed most of the circuitry, am in need of a custom mains transformer for the power circuitry, a 2.5mh inductor, a 2/3" vidicon tube yoke that suits for electromagnetic deflection and focus, a suitable enclosure and a few other things. I have to say a lot of the components particularly the transistors were not easy to get and I had to order them globally through Futurlec and Ebay, fortunately they were all there so now my circuitry is almost complete. Here below are schematic diagrams of the camera followed by pictures of my project in the works. The Amateur Television Handbook can be downloaded in PDF here.
Power supply circuit
3 circuit boards, power, video and timebase
2/3" vidicon tube
Camera adjustment pots board
Rear side of timebase board with plug to go to adjustment pot board
Camera adjustment pots board with plugs to connect to each board
Plugs coming from camera adjustment pots board
After a few months hiatus I've decided to get back into doing my camera project and have made great progress!!! The developments I've made with this project are as follows:
1: I needed to find something to mount the circuitry on for convenience as I'm yet to think of a suitable enclosue and I decided a plank of wood would be perfect to mount it all on for the testing stages, so I did just that and it looks pretty good.
2: I had to get a suitable transformer that meets closely with the specs of the one in the power supply schematic. As there isn't any ready made ones at electronic outlets like Jaycar or WES or Futurlec, I had to either get one custom made or use a series of transformers to get the required voltages. I got some advice from an electronics technician/hobbyist in which he suggested I use 3 specific transformers and did some mods to the power supply schematic, so I did just that and I got close to the specified voltages needed for the power supply.
3: I had to interconnect all the circuit boards and transformers so I using wire and bullet connectors I did just that and now have all of the electronics connected together! It certainly makes the setup look more messy and complicated! I made sure I labeled all connectors so I know which goes where.
4: I have scrutinized all circuitry for any mistakes, found a few and fixed them so the circuits should be all A okay now. Also added a few more components to complete the circuits.
5: I have began testing the power supply circuitry and there were a couple of errors which were 2 electrolytic capacitors positioned the wrong way around which puffed up, replaced them with new ones placing them in correct orientation. After that I got the power supply working perfectly giving close to the specified voltages so I'm happy.
Now all I have to do is complete the image pickup section which consists of the vidicon tube and yoke assembly and a C mount lens. As I don't have a yoke with magnetic focus I am considering borrowing one from my non working Sony AVC-3250CE. Once I get the image pickup section done it is ready for testing!!!
Anyways here below is the slightly modified power supply schematic and pics of the camera closer to completion with all of it's wiring!
Power supply circuit schematic slightly modified
Timebase circuit complete
Timebase circuit rear side complete
Video circuit complete
Video circuit rear side complete
All circuitry mounted on a wood plank
Closer view of the near complete camera circuit
Left side view of the near complete camera circuit
Right side view of the near complete camera circuit
Front view of the near complete camera circuit
The construction of the camera project is now completed (minus the enclosure) after spending the last month on and off finishing it off. I decided to borrow a camera yoke assembly with tube from my non-working Sony AVC-3250CE camera and fit it to my project to complete it and have also scrutinized the circuitry to make sure it was all correctly layed out and fixed up the few mistakes I made. Then I powered it up and to my horror the 7815 15 volt regulator went bang and a transistor went smokey, I checked it and realized I made a very dumb mistake of connecting the ground pin to the +30v input and the input pin to ground, man what was I smokin that day to make such a dumb mistake lol??? Lol jokes, seriously though that mistake really screwed up a number of components and so I had to hunt for the faulty components and replace them.
Getting more technical advice from one of my contacts, he listed some of the possible faulty components and I have replaced them then I powered up the camera again and fortunately no bangs but the 7815 regulator I replaced was fluctuating violently in voltage which was due to overheating so I put a big heatsink on it and that fixed that problem. Then I really started testing the circuitry out and was not getting a picture but was getting noise output which looked cool but not what I wanted and then checking the tube I saw that it was broken from stress fracturing due to the fact I tightened the securing springs He-Man tight!!! So there goes one vidicon tube unfortunately.
I replaced the tube with my old tube that I sunburned in my Sony AVC-3200CE and have powered it up again and was getting a dash like pattern that moves in all directions and have been doing adjustments to try and get something such as the line frequency, the sync amp, target voltage and other adjustments but no luck getting a picture. So the fault finding continues. I believe the video circuit works good as I get noise coming out when I touch the target with a screwdriver, the fault lies somewhere in the timebase circuit.
I also have been testing the horizontal and vertical and focus output current, the focus was getting some current, the horizontal and vertical didn't appear to be outputting any current according to my multimeter however one of my contacts said it's in milliamps and the current waveform for both should be a sawtooth waveform, so I will have to somehow find out how to test the current waveform as I am not sure how to do that as CROs generally test voltage waveforms. I also tested the horizontal and vertical voltage waveforms and am getting a pulse spike on the horiztontal and for the vertical initially it was a ripple but when replacing more transistors I was getting a positive and negative spike pulse. Not sure if those voltage waveforms are what I am meant to be getting but will be asking further technical advice from my contacts.
Anyways I am very happy that the project has progressed this far and it should hopefully not require too much more bug fixing before it becomes functional. Here below are pics of the final construction phase and testing of the camera plus the circuit diagram with common equivalent replacement transistors and chips which are easily available at Jaycar.
Video circuit with equivalent common transistors listed in red
Timebase circuit with equivalent common transistors and ICs listed in red
Deflection yoke borrowed from my non-working Sony AVC-3250CE camera
Deflection yoke now fitted with bullet connectors ready to plug into my camera circuitry
Camera project construction fully complete minus enclosure
Strange picture noise output due to the vidicon tube being broken
The dash pattern I am currently getting from the camera after replacing broken vidicon tube. This pattern flows in any direction depending on the line frequency adjustment.
Here is a video of this camera in action outputting to the screen that dashed patterning which flows in any direction depending on the line frequency adjustment.
Horizontal coil drive output voltage waveform
Vertical coil drive output voltage waveform
Vertical coil drive output voltage waveform after changing some transistors suspected to be faulty
I have been over the last couple of weeks locating and fixing the faults in my vidicon camera project and guess what, the camera is now making pictures WOOHOO!!!!! :D The pictures are far from perfect but are good enough to be recognizable and for me to say the damn bloody thing works! :) Now in the following paragraphs and pictures I will explain what I've done to fix the faults in my camera to get it to work.
Firstly I have been receiving a lot of advice from VTR/camera collector Richard Diehl from Labguysworld.com, he has given me such valuable technical advice to help me along the way to get the camera to it's current status of operation and has even made some modifications to the schematic adding more caps to the ICs and to the vertical scan section, thank you Richard, your help is most appreciated :D! I also have been getting a lot of help from vintage electronics collector John Hunter who is an electronics wiz and a huge collector of vintage electronics especially old TVs and has his own website featuring a portion of his collection, he has helped me as well with the camera and recently I've visited him and he has kindly gave me a large amount of vintage TV/video gear and also a Tektronix TAS-475 100MHz 4 channel oscilloscope which is an absolute valuable tool for my camera project and other projects and has been a huge help in me getting this camera going, thank you John!!! :D
From the advice of Richard the timebase circuit schematic is now modified with extra capacitors added, also the 4.7uF cap at the collector of TR19 is changed to 52uF, reason for that will be given further down. I also added a 75 ohm resistor to the video circuit as well, reason for that will also be given further down. Here is the two modified schematics:
Timebase circuit modified with extra capacitors added
Video circuit modified with a 75 ohm resistor at video out
My awesome new Tektronix TAS-475 100MHz 4 channel CRO