Great news
Thank you for sharing the datasheets
Fraser
While it's a very different camera, the 7290 (non-A) is mentioned here so I'll include some info on it too. I got one a few months ago with some intermittent issues which I eventually traced down to a regulator, having some problems getting reliable startup behavior, but it is imaging, and I've got some of my first benchtop views in SWIR.
Video is taken with an RG1000 long pass filter and an Ocean Optics LS-1 tungsten halogen lamp as illumination, though the desoldering iron pictured glows fine in SWIR when powered up!
As I mentioned, the internals of the camera are very different even though the function is the same. The tube used is a different brand and model - mine uses a "Cohu Electronics Inc 6810033 002 Rev K, MFG by Cletronics 5178 02 2374" on a sticker marked "MOD: 5204-5000/0000", the tube voltage is higher (+500V is marked on the silkscreen but with maximum adjustment my camera is only managing about +470V), and many of the components are older and are model numbers that return no datasheets or sources - probably renumbered parts, but definitely different and harder to ID than the ones used in the 7290A. Had to replace a LM78MGCP with an NTE953 regulator to get mine running, and it's used as the voltage reference for a switching transformer that generates the high voltages - instead of measuring the high voltage down as feedback, you just set the regulator's output voltage with a potentiometer and it multiplies it up with the transformer. This unit has a built in manual focus knob which moves the tube physically from the front panel and has no filter slot integrated, so you have to slap the filter on the outside of the lens.
A couple pictures of the single board with the tube in place, apologies for the focus, this camera always gives me some trouble with it and its depth of field seems to be a bit small.
Not exactly sure which the target voltage pot you mention on the other version is, but I'm tackling the oscillator issue first to get it to start reliably - going to try grafting a programmable oscillator into the crystal holes because the frequency is basically impossible to find. Worth mentioning that this is with a top and bottom aluminum plate removed with high voltage warnings, but which also give it some structure, the front and back plates are basically just held on by the interconnects at this point.
That camera is indeed quite different than the 7290 I have (resembles more the 7290A then the 7290). About the tube, seeing now the pictures, I think the "Cohu Electronics Inc" is related only the the yoke surrounding the tube, but I would expect the vidicon itself is still the hamamatsu N2606.
It there somewhere a type number on the PCB silkscreen? This might give you an indication who was the OEM of this camera, and might allow you to find the service manual like was the case with my version.
The COHU reference on the deflection coil assembly could actually be a clue to the cameras manufacturer. COHU were/are a manufacturer of specialist cameras. They could well have made the later 7290 and 7290A cameras. The deflection coil assembly states that it is “COHU” but actually manufactured by ‘Cletronics’
This page gives an insight into COHU as a camera manufacturer........
https://www.smecc.org/cohu_inc_-.htmThey certainly manufactured specialist Vidicon cameras and I own some of their more modern CCD 6400 series cameras designed for scientific and medical applications
Fraser
I will search for some COHU Vidicon camera service manuals and compare the designs and component identifiers used as that can provide corroborating evidence that it is a COHU design.
The more I think about it, COHU would have been a very likely candidate for a SWIR Vidicon camera as they have both the expertise and the ability to create custom designs for specialist applications such as tube based radiation resistant CCTV for use in Nuclear power stations. Tubes still have their uses in such situations
Company history....
http://www.fundinguniverse.com/company-histories/cohu-inc-history/Fraser
The COHU 2800B looked like a camera of similar vintage to the ELECTROPHYSICS original 7290but sadly there is very little information on vintage COHU cameras available on the internet. I will have to bo some more digging
Fraser
COHU 8120 ..... another possible basis for the the 7290 camera electronics ?
Well I failed in my attempts to identify a COHU Vidicon camera that matches what we have seen in the Electrophysics 7290 later model cameras. There is just too little information on the internet due to their age and I did not find any useful manuals or service information for the same reason. COHU remains a possibility but not one that I can currently prove. The 5300 series looked to be the last Vidicon based series from COHU but I strongly suspect a smaller diameter 2/3” Vidicon tube is used in that camera. In 1997 there is no sign of a Vidicon based camera on the COHU Electronics division website (via Wayback Machine). All listed models are CCD based. There remains the possibility of a custom order from Electrophysics but I have no proof of such.
Fraser
By the way, the later version of 7290 pictured in this thread is using components from 1990 (weeks 22/09 and 24/09) according to the date codes. The fact that the large IC and deflection coil assembly share the same production date suggests that the deflection coil assembly was in production and not an ‘old stock’ part. I still think that the use of a COHU marked deflection coil assembly that is also marked up as being made by another company is a bit of a giveaway as to who made the later 7290 cameras. Why would Electrophysics go to a camera manufacturer like COHU to buy the deflection coil assembly when such could be procured from the OEM or one of many other 1” Vidicon tube Deflection coil assembly manufacturers ? It is possible that the Vidicon tube camera production moved to another company that took the COHU parts stock but then I would expect a parts manufacturing date discrepancy.
Fraser
OK, my investigations suggest that this could indeed be a COHU product. The deflection coil assembly is from a COHU 5200 series 5204-5000 as shown on the label applied to the side of the assembly
whether the rest of the camera electronics comes from a 5200 series camera I cannot say at the moment. It is unlikely that he manufacturer of the 7290 ripped the deflection coil assembly out of a COHU 5204 camera and COHU are unlikely to place a full camera identity on a spare part. More likely it would have just the part number.
The COHU 5200 series use a 1” Vidicon tube and were known for their deployment in scientific roles with various different 1” Vidicon tubes fitted. Sadly I cannot find a manual or schematic but I am still searching.
Such a 5200 series camera was deployed on a Canadian telescope in 1984 as part of its guidance system. That date places the model close enough to the 1990 production date of the later Electrophysics 7290 camera detailed above to be a viable basis of its design.
https://www.jstor.org/stable/40679113?seq=1Fraser
I do believe that I have found the corroborating evidence that I was searching for. Please look at the attached pictures of the COHU 5222-2000 camera and take note of the rear panel detail. Then look at the pictures provided of the late 7290 camera internal parts. Note the area that I have highlighted..... the 9 pin D type connector and the focus control in close proximity to it. They even extended the focus shaft with a hulking great flexible coupler ! I believe the ‘donor’ camera electronics have been identified
It is a COHU 5200 series camera
The COHU 5200 series camera electronics package appears to have been rehoused to disguise its identity or to match the previous Electrophysics SWIR camera design. The 9 way D type connector is no longer visible from outside the cameras casing.
Now to see whether the 7290A is also a 5200 series COHU camera chassis
I wonder if a COHU 5200 series camera service manual is available somewhere on the internet, or even to purchase ?
Fraser
Right.... some more clarification...... the donor camera is a “5000 Series” unit from COHU. COHU have a very complicated model numbering scheme so it all gets a little confusing. Look at the attached images of another 5000 series camera. It’s ID plate calls it a 8000 series model (8741) yet its side markings clearly show “5000 series” and the tell tale 9 pin D type connector is still present and in the same location adjacent to the focus control
Also note the optional “Phase” control markings that correlate with the unpopulated PCB switch position on the 7290 PCB.
I must say I have enjoyed identifying this later model Electrophysics 7290 camera. The fact that it is a COHU design may also explain why the otherwise very helpful Lorraine at Sofradir cannot release the schematic diagrams. They are not theirs to release.
Fraser
I think you've got a match, thanks for the exhaustive research! I'll add that in addition to the 9 pin D sub connector and the unpopulated switch, the black plastic part right in the center of the back of the board of the camera is a bridge rectifier, which definitely made me suspect a 12VAC input or similar in another design. The lack of controls on the rear of my camera (four missing adjustment pots) and the fact that everything is point to point wired instead of directly mounted to the board point to some kind of retrofit or changing design/parts source. I haven't seen any manufacturer markings on the board itself, but it's clear that there are a lot of options not populated/configured - lots of installed header pins ready for a jumper block, some of which aren't well labeled.
Something to add to your connector topic, though: The "portable" version of the 7290A uses a ~6 contact connector in the same form factor (I replaced it for a barrel jack, and don't remember where I put it....). I got a hold of one with the built in NiCad pack built in (long dead) and it actually used more than four contacts from the power connector, piped them into a board with a relay to switch out the battery when connected to DC power and which held the regulators, but then they just had wires from the board to regulators mounted on the bottom chassis, so the whole inside of the camera was a bit of a bird's nest. It looks like they had a 12VDC input for the camera as well as a higher voltage charging input, at least, all through the power connector in the rear. I pulled the battery, the relay board, and attached some of the stray wires so that it can power up off of just 12VDC like the non-portable variants.
I must say I have enjoyed identifying this later model Electrophysics 7290 camera.
We can see that!
Great research and as always an interesting read.
I am sad that I cannot provide a schematic, or even a user manual however
The 7290A looks different. It may, or may not be of COHU origin. That is an investigation for another day. I will start by looking at the label, if any, on the deflection coil assembly
Fraser
I have just completed a careful inspection of my Electrophysics 7290A camera. I intend to sell it so had to be very careful and did not wish to disturb any connectors that were glued in place. As a result, the pictures are less than great, but adequate for my needs.
I was not surprised to find a pristine interior to the camera as it has seen very little us in its life. I studied the mechanical and electronic design and have come to the conclusion that the 7290A is a custom build and is not based on a commercial camera chassis. The 7290A does use the same make of deflection coil assembly as that used in the COHU but its mounting arrangement and all other aspects of the cameras design differs greatly from what we have seen in the COHU based camera. There is no COHU ID label on the deflection coil assembly, or anywhere else for that matter.
I will upload the pictures of my 7290A shortly.
Everything about the 7290A looks to me like a camera that was designed from scratch to fit its specific casing format. The complex back-focus mechanism has been replaced by the simpler ‘adjust, then secure’ 'sled' design found on other, later generation, vidicon cameras. The whole sled and twin ring support system for the deflection coil assembly looks bespoke and 'small production' rather than a mass produced casting as found in the COHU 7290 camera. Even the small riser blocks that elevate the support rings are hand made, but to a good standard. The PCB's are of acceptable build quality, if a little weird looking in terms of the PCB tracks and component positioning. The only really 'how ya doing' questionable design choice is the very unconventional heat sink plate attached to a TO220 format component. The 'heat sink' is long and lies across the top of the deflection coil assembly chassis. It looks unprofessional and is a mechanical design disaster in terms of transmitting vibration and torque to the TO220 package and its solder joints. No effort has been made to stabilise the 'heatsink' to prevent its movement. Definitely an afterthought !
It could be that the 7290A camera design is refined to get the best possible performance out of the vidicon tube, but that is just supposition on my part. There is no screening can around the tubes target pre-amplifier and that surprised me somewhat. Such a screen is often needed to reduce noise pickup in the sensitive pre-amplifier stage.
Pictures coming soon
Fraser
Electrophysics 7290A pictures