Ben321,
As you have named me in your request for help, I will provide a response.
Please try to understand the following…..
1. Many of us on the forum have busy lives so cannot always get involved in other peoples problems.
2. Personally, I have been very unwell since mid August so in no condition to offer much help to anyone, especially any sort of investigation into a fault.
3. We are all unpaid volunteers with lives of our own and whilst many of us help when able, please do not be surprised if we prioritise our life commitments higher than helping others to fix equipment via a forum.
4. People can only help to repair equipment if they have the required knowledge and information available to them. Repairing equipment remotely and relying on others to take measurements is both challenging and time consuming. I tend to repair equipment on my workbench where I can work efficiently to quickly narrow down the area of a fault. Remote repair is more involved as detailed instructions need to be written. I reverse engineer many camera PCB’s in order to repair them. Schematics are a luxury in this realm of electronics. I do not reverse engineer PCB’s remotely.
5. When someone buys a piece of equipment that turns out to be faulty, they are best advised to return it to the seller if they do not possess the knowledge to repair it. Repair can be an involved and protracted “adventure” for those unfamiliar with an equipment. It is unfair to keep the faulty item and expect someone else to diagnose it for you on their own time and free of charge.
6. You have thrown money at this project and I recall you unnecessarily spent a lot of money on a genuine power supply when any decent 12V power adapter would have worked perfectly fine. You then throw a large amount of money at a PICO digital Oscilloscope when a vintage cheap 20MHz analogue oscilloscope is all that is needed to diagnose and repair this camera. Without the required knowledge of this camera technology, you are throwing good money at it unnecessarily. I suggest that you stop blindly throwing money at this project.
7. The image that you have provided tells us absolutely nothing about the fault location within your camera. Treating the camera like a “mystery box” and trying to interpret its video output is not the most efficient way to diagnose a fault. You have to get inside the unit and “get your hands dirty”. Only when you have established which areas of the cameras PCB’s do what, can you move forward with diagnostic steps. I will list some key points in the diagnostic path below but you need to research the underlying principles of Vidicon camera technology if you want to diagnose the location of the fault, if indeed it is a fault and not an adjustment that is required in this elderly camera.
a) Power supply rails - identify and monitor all power supply rails and their voltages in the camera. Power supplies are a common failure in elderly equipment. Determine the correct rail voltages from silk screen voltage details (if present) or by reverse engineering the circuits. There will commonly be low voltage supply rails for analogue amplifiers, oscillators, logic circuits and the tube heater. Higher voltage power rails will feed the deflection coil drive circuits and internal parts of the tube. Referring to descriptions of Vidicon camera tube voltages will help here. Any electrolytic capacitors that look suspect, or if heavy ripple is present on a supply rail, requires the fitting of fresh new capacitors as they dry out over the years. Power supply issues can cause all manner of unusual fault symptoms.
b) Using an oscilloscope, monitor the Horizontal and Vertical tube yoke drive to ensure that all is well with those oscillators and drivers.
c) Use the “half split” method to monitor key points in the analogue video path from the Tube target, through to the BNC video output connector. In the case of a camera, you use the output of the Vidicon tube target pre-amplifier (NOT the target terminal itself as it is very high impedance). This is the “test signal” that will be traced through the video signal path. Make sure that the camera has a lens fitted and is focussed on a test scene (not too bright a scene though !) There will be a video signal representation of the test scene present at the output of the tube target pre-amplifier that you should study it to see if it is correct. The output is the result of the H and V scans of the electron beam on the target stimulating the signal production at the target output. If the target pre-amplifier output appears normal and reacts to a hand waved in the image path, you have your test signal to trace. Choose a point further down the video signal path (normally half way down the path) and monitor the video signal with an oscilloscope. Does the signal appear very similar to that seen at the pre-amplifier output ? If not, you need to carry out more tests in the video stages towards the tube end of the system. If all looks normal, proceed to check further down the video signal path, half way between the last test point and the output BNC connector. Does all look normal ? If not, you need to carry out more tests on the signal path between your previous test point and this current test point. If all is normal carry out more tests using the half split method. You should quickly locate the area where the video is degraded, suffers interference or parts of it disappear. Be warned, high voltages are present in these cameras so do not fry the front end of your oscilloscope ! The bit depth is not an issue when repairing these cameras. 8 bits DSO’s with a true 10MHz bandwidth and 100 MS/s sampling rate work just fine in such diagnostic routines. Along the video signal path you SHOULD see the original plain “video only” signal become amplified and combined with the usual monochrome composite video signal components of “front porch”, “back porch”, “Blanking”, “Horizintal Sync” and “Vertical Sync”. If an unusual additional signal appears in the video signal between two of your test points, use the oscilloscope to determine whether it is a random signal or structured, such as a clock signal. Then investigate that area of the signal path circuit to track down the abuse of the signal ingress onto the otherwise correct signal path.
Well that just about sums up what you need to do. You should do some reading on analogue Vidicon camera circuits and find some service manuals for monochrome Vidicon CCTV manuals from companies like Panasonic. (Google “Vidicon camera service manual” ) The service manuals will provide pictures of what a typical signal looks like along the signal path etc. They will also give you an idea of the voltages that you are likely to see in your camera at various points in the drive and signal paths.
You may think that your camera is different to a monochrome Vidicon CCTV camera, but you would be mistaken. Whilst tube bias voltages differ, it is the same technology base. FJW used to adapt standard Panasonic Vidicon CCTV cameras to SWIR cameras by installing a new imaging tube and modifying the power supply circuits to meet the new tubes requirements. The Panasonic CCTV camera became an FJW 85400A 1800nm SWIR camera. I may still have the service manual for the original Panasonic CCTV camera that they used but will need to check. It is not the same circuits as your Micronviewer but it shows signals and voltages common in this technology.
Fraser
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