SWIR Electrophysics Micronviewer 7290A - User manual ? - Page 1
Forum section: electronics / general

author: Fraser
author_rank: Super Contributor
timestamp: December 15, 2018, 05:55:44 pm
content: Hi all,I own a very nice example of an Electrophysics Micronviewer 7290A SWIR cameraI am writing this post here, in the Thermal imaging sub forum, as this camera falls into the region between Near Infrared and MWIR thermal imaging cameras.The 7290A uses a PbS coated Vidicon tube and has a bandwidth of 0.4um to 1.9um. It can operate as a thermal imaging camera for items with a surface temperature of 250C or higher.These cameras are commonly used on production lines to inspect food stuff (fruit etc) and in science for imaging Laser beam shapes. The military also make use of such SWIR imaging and even use image fusion with the output of LWIR cameras.Now that I have such a camera I will experiment with its capabilities to see just how useful, or not, the SWIR band actually is for a hobbyist.Does anyone else own one of these cameras please ? If so, would you care to share you experiences with it here and would you have a copy of the user manual that you can share as my camera came without one.Fraser

author: Fraser
author_rank: Super Contributor
timestamp: December 17, 2018, 02:55:11 pm
content: I now have the user manual thanks to excellent support from Sofradir in the USAFraser

author: Vipitis
author_rank: Frequent Contributor
timestamp: December 17, 2018, 06:21:21 pm
content: Given the vastly different spectrum of wavelengths, does this allow you to see through other stuff? Like LWIR let's you see through plastic balloons or plastic bags.

author: Fraser
author_rank: Super Contributor
timestamp: December 17, 2018, 07:11:37 pm
content: Yes. An example would be its ability to image a hot object through glass or to see through visually opaque silicon wafers. SWIR works somewhat differently to MWIR and LWIR. It can image reflected photon energy. This is used to good effect when examining works of art. The art is illuminated with suitable Tungsten Halogen lamps. In some cases the artists layout pencil sketch becomes clearly visible. SWIR cameras can also image through water vapour. It has military applications due to its better imaging of some targets than thermal cameras.Fraser

author: DaJMasta
author_rank: Super Contributor
timestamp: May 18, 2020, 08:09:44 pm
content: Just picked up one of these units listed as not working myself and fancy a repair attempt. First things first, it came with no power supply, and while the documentation I've seen says 6W and 500mA (so 12V?), I don't know what connector it uses or whether there are other rails on the other pins for it. If you have any info it would be helpful, but I'll probably crack it open to try and power it up (and maybe replace the connector with a more standard one) in either case.EDIT:Well I guess I asked too soon. Took out some screws out of curiosity and found you can just remove the whole top with the top four little screws, nice easy access. From there I could see the power connector only had two pins soldered, and the main TO-220 voltage regulator is an LM2940 rated for 10V, so the input has to be a minimum of about 11V to turn on, so I gave it 12V on the pins on the back connector from the bench supply and it powered up just fine. Draws about 750mA tops when starting, settles to about 550mA. Since the connector is panel mount, I'll probably just swap it for a standard barrel jack and use a 1A rated adapter. Easy!I need to connect a lens (didn't ship with one) and do some testing - preliminary video output doesn't look like the sync is correct, but it's changing brightness when I put my finger in the way of the aperture, so it seems the tube is alive. Hope to be viewing in limited SWIR in short order!

author: Bill W
author_rank: Super Contributor
timestamp: May 19, 2020, 02:16:19 pm
content: Quote from: Vipitis on December 17, 2018, 06:21:21 pmSupposed to be good for seeing into 'blacked out' car windows as it goes through both glass and the black film.Had a loan camera core once, and a loan lens, and a loan interface. However they failed tobe with me all at the same time to use !Bill

author: DaJMasta
author_rank: Super Contributor
timestamp: May 22, 2020, 05:42:41 am
content: Been working on my unit and I have yet to get good output. I have the -E variant which is CCIR-50 output, but that seems to be recognized alright on my USB capture device, and looking at the output on a scope, I'm definitely not getting image data that it's not capturing, just all white with some noise when I mess with the lens (coupling effects, I think).Been tracing things out to see what they are, but so far it's all red herrings. The high voltage supply seemed to be bad, but it turns out it's just being shut down after a second or so and is actually reaching full voltage. Traced out the feedback comparator that drives the switcher mosfet and so far, the only lines I'm seeing from it are coming from the tube board itself, so I think there's another connection - maybe a control circuit on the output of a high voltage line to the tube board, that when its switched off, the comparator turns off the HV supply.I did add a barrel jack for power on the back, and since it was too small to use the power jack hole, I 3d printed a plug for the unused viewfinder output to fit the barrel jack and added it in. I then noticed that my unit didn't have the piece for holding the filter in place, so I designed and 3d printed one with a retaining ring and scrounged a 1 inch 705nm long pass filter to put in there - looks great (and the black PETG it's printed in is opaque at least to 1100nm) and fits will, when I finally have a working unit I'll upload the designs.I basically haven't touched the smaller control board yet, the larger board has the HV supply, the external sync circuits (the two DIPs towards the back of the unit), some timing generation, and even a microcontroller. I think it has the first stage analog amp as well since the tube board only connects to this board, but I haven't yet traced it out.Does anyone have any info on the tube itself? It seems a few pins are basically dead shorts, but I have no experience with camera tubes, let alone ones with specialized detectors.

author: Fraser
author_rank: Super Contributor
timestamp: May 22, 2020, 12:14:00 pm
content: It is a standard vidicon tube in most respects except the target material. I will see what data I have on it. Sadly I was unable to obtain any schematics for the camera from Electrophysics as they prohibit it release of such, even for older modelsI am aware that someone obtained a schematic for the earlier 7290 (not A) model but I do not think I managed to obtain those either. I will have to search my archives. I will see if I can help but my unit is “as new” so I have not had to work on its electronics and do not really want to poke around too much as I intend to sell it when I find a suitable buyerThese sell for serious money when working so you got yourself a bargain. From memory it is using a Hamamatsu tube.More details to follow.In the mean time, I recommend you search for Vidicon CCTV camera schematics, service manuals and magazine DIY camera projects from the 1970’s. These will help you better understand the needs of a avid icon tube and will provide waveform data as well. Even if you find the current fault condition, you may need to fine tune the biases on the tube due to ageing.Fraser

author: Fraser
author_rank: Super Contributor
timestamp: May 22, 2020, 09:15:37 pm
content: Sadly there is not much more in my archives to help you.I attach the user manual in case it is of use to you.Fraser

author: Fraser
author_rank: Super Contributor
timestamp: May 22, 2020, 10:36:58 pm
content: I believe the tube used in the 7290A is a Hamamatsu N2606 as used in the Hamamatsu C2400-03 and C2741-03 IR cameras. The C2741-03 cameras datasheet may be found here.....http://alacron.com/clientuploads/directory/Cameras/HAMAMATSU/c2741-03-Datasheet.pdfFraser

author: Fraser
author_rank: Super Contributor
timestamp: May 22, 2020, 10:40:04 pm
content: Dage-MTI also offer a camera that uses the N2606 tube. It was a popular choice for IR and SWIR camera designs at the time.https://dagemti.com/wp-content/uploads/2015/04/LSC70spec.pdfFraser

author: Fraser
author_rank: Super Contributor
timestamp: May 22, 2020, 10:57:29 pm
content: An article that may be of interest......https://museumsbau.de/wp-content/uploads/2017/12/burmester_bayerer_1993.pdfFraser

author: Fraser
author_rank: Super Contributor
timestamp: May 22, 2020, 11:09:09 pm
content: Another document that is worth reading. It details the bias needs of the vidicon etc in Chapter 11......http://www.r-type.org/pdfs/pctdh.pdfFraser

author: Fraser
author_rank: Super Contributor
timestamp: May 22, 2020, 11:25:27 pm
content: The Hamamatsu N2606 IR Vidicon was discontinued back around 2008 as detailed in a quotation to be found here. Just look at how much these N2606 based cameras cost !http://userweb.eng.gla.ac.uk/william.ward/OPTOELECTRONICS/Glasgow%20Uni%20C2741%20Quote%20220108.pdfFraser

author: DaJMasta
author_rank: Super Contributor
timestamp: May 23, 2020, 05:53:11 am
content: I appreciated the extra bit of library, unfortunate that there's not many discussions of driving the tube specifically in the literature directly pertaining to it! I poked around a bit today, the 300V was a bit high so I turned it down, the -150V was a bit high but seems better now that I'm checking it again, though the -60V was -77 - which makes sense since it comes from a 2N6520 who's base is biased in the middle of 1M resistors, so I'm not really sure where 60V on the silkscreen is coming from. Voltages that seem in the right ballpark are present at the tube (nothing in the <-40V range, but some -16V range, 450V, 415V, and 300V), and focus, definition, and alignment/centering pots do have an effect on the image, though nothing gives an actual picture - you can just adjust the black vignetting on the edges. Adjusting the target potentiometer doesn't seem to have an effect I can see. I see voltages on the coils, but I don't see activity, so I'm not sure there's any scanning happening - will be looking into this next.Alarmingly, though, I found a bodge that probably wasn't done at the factory. The positive supply for an LM358 was attached to a transistor connected from a line to the tube and then over to the other board - was hovering a little below 12V, but the trace on the board to the supply line was a 10V one which had been intentionally cut by a file. Different kind of wire from all the other bodges on the boards, I removed it and reconnected the LM358 supply rail to an actual supply line, and the line going to the other board seems happier and it works the same. There are a few more bodges on the boards (and at least some are definitely from the factory), so I'm hoping this won't rear up again.Found another thread here which shows pictures of their boards.... and at least some are a different revision than mine. Different trace layout, different part orientation.... it's probably not useful for my debugging:https://www.eevblog.com/forum/repair/electrophysics-7290a-vidicon-camera/msg744441/#msg744441And finally, it may be really, really easy to change between CCIR-50 and RS-170 output formats... a little jumper next to the micro on the larger board. If the board is installed normally, it's in the top left while looking at the side (lens to the left), on the side facing the tube.

author: _Wim_
author_rank: Super Contributor
timestamp: October 03, 2020, 04:27:18 pm
content: Hi, just picked up an older 7290 (non A version) on Ebay. Does any one has a user manual or datasheet for this one? So far all info on the net seems to be about the 7290A, and most info for the 7290A was found right here as posted by Fraser.The oldest page (1998) for "www.electrophysicscorp.com" found on the internet wayback machine is already about the 7290A:https://web.archive.org/web/19980701075430/http://www.electrophysicscorp.com/prodlib/7290grp.htmSo the 7290 must be dating before that.So far the differences between the 7290 and 7290A that I can see is that the 7290 does not have the optical filter slide, different controls and connectors at the back, and a built in power supply.I just purchased the unit on Ebay, so it has not arrived yet. The seller has made some test with is, and it should be working (after the non working and non repairable 7215 I bought, I was now looking for a working unit...)

author: _Wim_
author_rank: Super Contributor
timestamp: October 03, 2020, 07:49:25 pm
content: I also asked Lynred (which I think is the company that used to be sofradir) for the manual, so hopefully they have still something in their archive. Google has for once turned up empty handed...

author: _Wim_
author_rank: Super Contributor
timestamp: October 05, 2020, 06:46:07 pm
content: I got a reply from Lynred: "Further to your request please note that LYNRED do not produce cameras but the detectors that compose cameras."So great that they answer quickly, but unfortunately, no further assistance there.

author: _Wim_
author_rank: Super Contributor
timestamp: October 05, 2020, 07:48:36 pm
content: I found a Dutch magazine from 1988 that mentions the 7290 as a new product. Unfortunately, not much technical information is provided. But nice for the archive.Translation from Dutch:Electrophysics has designed a micron viewer, model 7290, for detecting IR radiation from the visible range up to 1800 nm. The micron viewer consists of a TV camera with 1 inch Vidicon recording tube and a Pb O-PbS photoconductive plate.The image that is focused on the Vidicon plate causes an increase in conductivity of the plate material, according to the intensity and the spectral response. The resulting electrical image, which is formed on the material of the plate, is read by the scanning electron beam of the camera. Some applications of the micron viewer include: detection of IR lasers and LEDs, study of semiconductor "wafer" defects, control of heat treatment processes, detection of objects at temperatures above 250 ° C, and analysis of signatures or fingerprints.

author: Fraser
author_rank: Super Contributor
timestamp: October 05, 2020, 08:52:05 pm
content: I will look in my archive to see if I have anything about the 7290 modelFraser

author: Fraser
author_rank: Super Contributor
timestamp: October 06, 2020, 10:47:56 am
content: My POC at Sofradir was Lorraine Connell in the Sales team. She tried to be as helpful as she was permitted to be.lconnell@sofradir-ec.comOrel_Sales@sofradir-ec.comThat email address may redirect to her new one so worth trying ? Alternatively, send an email to the sales team with an instruction for it to be passed to Lorraine. It could just be that your email went to the wrong person on the team.Looks like Lorraine still works fir the company.....https://www.linkedin.com/in/lorraine-connell-a2750a17Lorraine told me that she could not provide a schematic as Sofradir was continuing support of the Micronviewer cameras. She did supply me with a user manual however so might be able to do the same fur your earlier model.Fraser

author: Fraser
author_rank: Super Contributor
timestamp: October 06, 2020, 10:59:11 am
content: Dr Hobbs needed a service manual but Lorraine could not help him and he is a man of some high repute who I feel sure Electrophysics would have helped, if able. Dr Hobbs may have an owners manual for his camera though. He provided contact details. I believe I contacted him in the past but he has moved on from the faulty 7290 and did not find a schematic.https://groups.google.com/forum/m/#!topic/alt.lasers/E6Dk1nF26eUhttps://alt.lasers.narkive.com/eJMl2ZhK/electrophysics-7290-ir-camera-schematic-service-manualFraser

author: Fraser
author_rank: Super Contributor
timestamp: October 06, 2020, 11:11:42 am
content: I can look out my 7290A user manual if you would like it.Vidicon cameras are pretty much a standard basic architecture and unlike the Pyro Electric Vidicon thermal cameras there is no additional chopper wheel mechanics and electronics. A standard CCTV vidicon camera can be modified to work with a SWIR vidicon tube so any references detailing the design of cameras using a vidicon tube are useful in understanding the 7290 series. I suspect the 7290 uses more discrete components than the 7290A as Electrophysics likely refreshed the design using IC’s that had become available since the first generation camera was designed. This is what happened in the World of Vidicon CCTV cameras and I suspect the 7290A refresh team did similarly using CCTV camera developments as a guide to their design.Fraser

author: _Wim_
author_rank: Super Contributor
timestamp: October 06, 2020, 06:55:58 pm
content: Thanks for the info. I yesterday wrote back to the original reply from Lynred pointing to the manual of the 7290A and more thoroughly explaining what I was looking for. If this does not work out, I will try to contact Lorraine Connell.

author: _Wim_
author_rank: Super Contributor
timestamp: October 06, 2020, 07:23:45 pm
content: I have just been contacted by Lorraine Connell (my question was forwarded to her via the original contact), so she still works for Lynred. She first provided my with the user manual for the 7290A. When I explained that I was looking for the 7290, she said she will need to look when she is back in the office at the end of the week.That is for sure excellent service for such an old unit, I which all tech companies were like that!

author: Fraser
author_rank: Super Contributor
timestamp: October 06, 2020, 07:40:13 pm
content: Lorraine is a lovely lady and if she can help you, she will. I was just about to upload the 7290A user manual for youThere is not a great deal of information in the user manual as you will no doubt have seen.I will upload the 7290A user manual and FAQ anyway in case it is of use to someone in the future.Fraser

author: _Wim_
author_rank: Super Contributor
timestamp: October 06, 2020, 07:54:21 pm
content: Great news!I was looking to find an explanation for the BNC connectors at back. One of the BNC connectors was labelled as “hd or vs in”, so I searched exactly for that: “hd or vs in”. This gave only 2 hits, one of them was for an ad of a “Ikegami Television Camera Model ITC-510” camera.Further investigating the Ikegami camera, I found to my surprise it looked identical to my 7290 camera (also based on a vidicon tube, but without special plate coating or SWIR viewing).The best part is that Ikegami do make full service manuals available (see attached).Currently looking on the Ikegami website (https://www.ikegami.com/old-products) for an equivalent of the 7290A

author: Fraser
author_rank: Super Contributor
timestamp: October 06, 2020, 08:36:46 pm
content: Excellent investigative workI have seen Panasonic Vidicon CCTV cameras used by FJW for their SWIR cameras so it is no surprise that Electrophysics used a modified camera from a large CCTV camera manufacturer. Why reinvent the wheelFJW used the Panasonic WV1414 as the basis of their SWIR Find-R-Scope cameras. See the attached picturesFraser

author: _Wim_
author_rank: Super Contributor
timestamp: October 06, 2020, 09:12:34 pm
content: Quote from: Fraser on October 06, 2020, 08:36:46 pmIndeed. Probably Electrophysics/FJW would have a hard time making an equal quality product, and cost wise it would be much more expensive due to the much smaller market.So far I have not been able to find on which type the 7290A was based, but I would expect it would also be an Ikegami camera (but maybe an OEM version)

author: Fraser
author_rank: Super Contributor
timestamp: October 06, 2020, 09:43:22 pm
content: I have been searching as well. I am suspecting a modified Ikegami PCB set with a custom/modified casing. I cannot find a likely candidate yet. I have taken a look at some pictures of the 7290A PCB's and there is a lot of post production modification which suggests to me that the camera was supplied configured for a standard Vidicon tube and then modified by Electrophysics. The many 'bodge wires' are not what I would expect of a production Ikegami camera.Thanks to your discovery, I am now a step closer to discovering the origins of the PCB's within the 7290AIt is likely based on a later model of ITC series camera as they certainly fit the spec. There was also the CTC2xxx series that are described in that Ikegami table as colour, yet they use a monchrome Vidicon tube.Having compared the 7290 circuits and its parts list with my 7290A PCB's, I believe I was correct in thinking that the 7290A was basically an update that used more IC's and a reduced discrete semiconductor count. Exactly what I saw in the Commercial CCTV camera designs of the era.Fraser

author: Fraser
author_rank: Super Contributor
timestamp: October 06, 2020, 10:44:31 pm
content: I am working my way through the many Ikegami ITC camera user manuals as they contain the parts list and schematics. A case of trying to spot similarities with the 7290A PCB chipset. I have already looked at the ITC-47 aka CTC-4700 and I agree that the 7290A is very likely an Ikegami product. The later cameras have the higher chip count that I am looking for so just a case of seeing if I can find a match.Fraser

author: Fraser
author_rank: Super Contributor
timestamp: October 07, 2020, 12:42:28 am
content: Well I downloaded all of the Ikegami ITC and CTC manuals that I could find and analysed the parts list and schematics. There is a definite pattern to the components used in different eras of camera and they do not match, or even come close to the design of the Electrophysics 7290A cameraThe PCB component marking for IC's also differs to that used by Ikegami. The manufacturer of the 7290A has elected to use a somewhat unusual IC ID format. "UP1" for an IC1 being an example. Other examples are UB1, UE1, UG1, UN1, UO1. Not an IC label format I have seen in any of the Ikegami manuals._Wim_, I think you got very lucky with your camera and discovered the true OEM of it. Sadly I think the 7290A is going to be challenge. Why ? ... well the 7290A was likely designed after CCTV had moved to semiconductor sensors and Vidicon tube based cameras had become restricted to science and other specialist applications. As such, Electrophysics may have found that there was no 'modern' Ikegami tube camera to buy and modify. They would likely have been restricted to companies making tube cameras for science use, such as Hammamatsu, but that particular company is in direct competition with Electrophysics so such an alliance is unlikely. That would possibly lead to a contract being raised with some small specialist company that had designers experienced in working with Vidicon tube technology. The chances of discovering that companies identity are slim and even if discovered, the schematics would be limited circulation and likely only existing within the OEM and Electrophysics (Sofradir/Lynrad). The casing of the 7290A has been designed to take the filter cartridge and has not been modified to do so. that strongly suggests a custom build from scratch, at least for the case. The large number of PCB modifications (bodge wires) might also suggest a smaller company developed the 7290A and had to iron out some issues in the production cameras. There remains the possibility that the design has been based upon that of another commercial Vidicon camera and just adapted to a new PCB layout etc. Interestingly the 7290AX model has an additional PCB for power management. That optional PCB looks to be the same designer and manufacturer as the other PCB's. Such a PCB would not exist in a CCTV camera, adding weight to the custom design theory.Finally, I need to check my camera, but from the pictures I have, it would appear that the 7290A is fitted with a relatively large Atmel IC on one PCB plus what appears to be a battery management processor on the AX model additional PCB (it has its own Crystal oscillator). These are not components of the Ikegami (or any other manufacturers) Vidicon CCTV camera era !All good fun but it is time for Bed now.... need some sleep !Fraser

author: Fraser
author_rank: Super Contributor
timestamp: October 07, 2020, 12:50:12 am
content: In case anyone is interested, I will be selling my 'as new' 7290A soon. I will likely market it towards those clever people who use such cameras to check the quality of their amazing Laser systems ! I am open to offers if anyone has a burning desire to own a SWIR capable cameraThe camera is fitted with an original equipment electronic viewfinder, will come with its original Power Supply and a spare power connector, plus the two ND filters and C mount 'hood' for laser use. A very nice 25mm lens is also available for itThe camera is very nice but I have no real use for the SWIR capability. I will ship internationally.FraserUK

author: _Wim_
author_rank: Super Contributor
timestamp: October 07, 2020, 06:28:40 pm
content: Quote from: Fraser on October 07, 2020, 12:42:28 amSounds indeed like a very reasonable explanation. If I would get lucky again, I will for sure post it the 7290A schematics also here.

author: _Wim_
author_rank: Super Contributor
timestamp: October 07, 2020, 06:33:47 pm
content: Quote from: Fraser on October 07, 2020, 12:50:12 amThat is a very nice set! If I had not just bought the 7290 I would be very temped...

author: _Wim_
author_rank: Super Contributor
timestamp: October 08, 2020, 06:17:12 pm
content: I was again contacted by Lorraine today, telling me she was unable to find the manual of the 7290. However, with the manual of the Ikegami and the manual of the 7290A posted by Fraser this is not really a problem, and I really appreciate she make the effort to look for it and spontaneously report back.

author: Fraser
author_rank: Super Contributor
timestamp: October 08, 2020, 06:44:21 pm
content: Lorraine is certainly a very helpful lady.When I last spoke with her they were in the midst of relocating. Sadly when companies move location a lot of documentation can end up mislaid or dumped in order to reduce storage requirements. This is what had happened when I asked ISG about the early Pevicon based Talisman service manual..... it has been lost over the years.As you say, with the 7290A manual and the Ikegami camera information, you are well set up on the information frontOne piece of information that would be very useful would be the Vidicon Tube recommended bias voltages. I do not think I have found the data sheet for the Hamamatsu N2606 and N2606-6 tubes used in these cameras.http://alacron.com/clientuploads/directory/Cameras/HAMAMATSU/c2741-03-Datasheet.pdfhttps://microwiki.org/wiki/index.php/Hamamatsuhttps://dagemti.com/wp-content/uploads/2015/04/LSC70spec.pdfFraser

author: Fraser
author_rank: Super Contributor
timestamp: October 08, 2020, 07:06:34 pm
content: This document does not contain the N2606 tube data but is still an interesting read and has a guide to setting biases.https://frank.pocnet.net/other/Amperex/hafo/ampvid.pdfFraser

author: _Wim_
author_rank: Super Contributor
timestamp: October 08, 2020, 07:09:43 pm
content: Quote from: Fraser on October 08, 2020, 06:44:21 pmI have been looking for that datasheet also, but so far no luck. I also managed to find a catalog that mentions them, but no real useful information in that.

author: _Wim_
author_rank: Super Contributor
timestamp: October 08, 2020, 07:21:35 pm
content: I did also find the price of the 7290/ITC510 in 1986 and the confirmation that in includes an Hamamatsu n2606-02

author: Fraser
author_rank: Super Contributor
timestamp: October 08, 2020, 07:52:57 pm
content: A paper on development of the N2606 Vidicon, written by Hamamatsu, may be found here:https://doi.org/10.1016/S0065-2539(08)60475-8Sci Hub reveals the papers contentFraser

author: Fraser
author_rank: Super Contributor
timestamp: October 08, 2020, 07:58:49 pm
content: An IR Vidicon Patenthttps://patentimages.storage.googleapis.com/26/ba/0e/43fa07fdfbe542/US3892966.pdf

author: _Wim_
author_rank: Super Contributor
timestamp: October 08, 2020, 08:06:02 pm
content: Quote from: Fraser on October 08, 2020, 07:52:57 pmNice one!

author: Fraser
author_rank: Super Contributor
timestamp: October 08, 2020, 08:26:45 pm
content: Interesting paper....https://museumsbau.de/wp-content/uploads/2017/12/burmester_bayerer_1993.pdfFraser

author: _Wim_
author_rank: Super Contributor
timestamp: October 10, 2020, 12:05:30 pm
content: Hi, I received the camera today and gave it a little test. Beam intensity was turned almost fully to max by the previous owner to get a usable image out of the camera, but this result in very slow updating (take more than 3 seconds when something is placed in the field of view to be fully visible). This means the vidicon is end of life, and replacements will be not easy to find I am afraid. It does still have sensitivity until al least 1525nm (highest laser wavelength I have), so it still might have some use for visualizing laser beams.In case anyone would still doubt this camera is based on the Ikegami ITC-510, their is some strong "hint" on the pcb...

author: _Wim_
author_rank: Super Contributor
timestamp: October 10, 2020, 12:16:25 pm
content: Some more internal pictures

author: Fraser
author_rank: Super Contributor
timestamp: October 10, 2020, 12:31:56 pm
content: _Wim_That camera looks to be in very nice internal conditionRegarding the availability of spare IR vidicon tubes, with regret I must advise that Hamamatsu disposed of all of the stock to companies like Electrophysics so that they could continue production of their SWIR cameras. From memory there was a $7000 minimum order value from Hamamatsu so individuals could not buy spare tubes from them unless willing to pay over $7K ! Electrophysics had some limited spares stock but it was very expensive due to rarity. I do not know if they have any left but it would be much cheaper to source another camera on eBay that has a better tube fitted.Electrophysics continued selling the tube based SWIR cameras for as long as stocks of the Vidicon tube permitted. Their cameras have a large customer base in laser labs so there was still demand for the cameras. This is also why these cameras still sell for serious money on eBay. Good ones are now rare and becoming scarce.I do not know of a way to revitalise your tube but in CRT’s there was something called cathode poisoning and there were techniques to revitalise the cathode emission surface to extend the tubes useful life. Tubes that have not been used for a long time also needed ‘conditioning’ of the vacuum. It may be worth you looking into this.Also be aware that over time the bias needs of the tube can change and adjustment of the various bias voltages may improve your cameras performance. Bill_W is the man to comment on that as he is very familiar with thermal camera Pevicon tubes that are basically a version of the a vidicon tube.Thank you for the excellent pictures of your cameraMine has no such helpful OEM identification on the PCB’s.Fraser

author: Fraser
author_rank: Super Contributor
timestamp: October 10, 2020, 12:44:11 pm
content: Some reading......http://www.ke5fx.com/crt.htmlAndhttp://www.thegleam.com/ke5fx/crt/sencrt.pdfA Vidicon is similar to a CRT in that it uses an electron Gun with Cathode emission to an Anode target. Cathode poisoning may be an issue with old Vidicon tubes as well ?Vidicon tubes in the 7290 cameras often get damaged by burn-in from abuse long before they ‘wear out’.Fraser

author: _Wim_
author_rank: Super Contributor
timestamp: October 10, 2020, 01:28:48 pm
content: Quote from: Fraser on October 10, 2020, 12:31:56 pmI will indeed try to bring all voltages and biases up to spec. Today was just a quick test. Visual inspection was indeed ok. No bulged caps or burned parts. Also checked with my E60, nothing gets extremely hot, so that also ok. Looks like this will be a fun project, and price was luckily not very high. I contacted Hamamatsu Belgium in the hope I could get a datasheet for the N2606. I will off course post it here also when I receive it.

author: Fraser
author_rank: Super Contributor
timestamp: October 10, 2020, 01:37:07 pm
content: An interesting side comment, the Electrophysics 7290 and 7290A apparently have some military sensitivity dating back to when the N2606 tubes were used in military applications. Sadly such information restrictions can remain in place long after any real sensitivity has passed into history. This may be why the data sheet for the Hamamatsu N2606 vidicon cannot be found on the web ?. EBay will not let me list the Electrophysics 7290A in the U.K. and state that it is on the U.S. Military list and only allowed to be advertised in the U.S.A with no export permitted !

author: _Wim_
author_rank: Super Contributor
timestamp: October 10, 2020, 03:14:28 pm
content: Quote from: Fraser on October 10, 2020, 01:37:07 pmThat is crazy! I have seen many modern SWIR Ingaas cameras listed on Ebay with much higher resolution and sensitivity (and unfortunately also much higher price), and these were available worldwide.A nice example is found here:https://www.benl.ebay.be/itm/NIT-WiDy-Sens-cooled-InGaAs-camera/274520123080?hash=item3feaaca6c8:g:Cn8AAOSw0MpfeYXhA "bit" above my budget however...

author: Fraser
author_rank: Super Contributor
timestamp: October 10, 2020, 03:23:02 pm
content: I agree.EBay seem to have some text filter on item titles that checks against a restricted items list. The title “Electrophysics 7290A” triggered a statement that the item was on a Military controlled products list ! I even tried different titles but the 7290A bit still triggered the listing rejection. That was a first in my experience and I bought the camera from France via eBay !Fraser

author: _Wim_
author_rank: Super Contributor
timestamp: October 10, 2020, 03:28:27 pm
content: These 2 have just popped up:https://www.benl.ebay.be/itm/Set-of-2-Electrophysics-7290-7290A-Micronviewer-Untested-For-parts-C485DS/233739306838?hash=item366bf2c756:g:WfwAAOSwM7tfBgw8Title also includes "7290A" and export IS possible. Ebay sometimes acts very strange (also the search function)! Maybe it is ok if listed "for parts"

author: _Wim_
author_rank: Super Contributor
timestamp: October 10, 2020, 04:02:16 pm
content: @Fraser, just I quick question, the user manual you posted states "Decay lag after 50msec:45-60%". I interpreted this as the time constant is 50ms (1 decay time constant is around 60%), and that after 5 time constant the image would be fully updated (so 250 to 300ms for a full update)In my camera (which uses the same tube, and normally this spec would be tube related) it takes more than 3 seconds, so I expect this is abnormal and probably due to the high beam current.But to be sure, if you place or remove object in front of your camera, how long does it take for the image to get completely updated?

author: Fraser
author_rank: Super Contributor
timestamp: October 10, 2020, 04:37:57 pm
content: I noticed very little ghost effect on my camera. It behaved very much like a normal Vidicon CCTV camera. If I saturated the Tube target of any Vidicon it would suffer short term ghosting but that is to be expected.Your units 3 second delay sounds very bad indeed and suggests that the target is not at all happy and suffering some form of saturation effect. I am no expert on Vidicon tubes however. I have worked on Vidicon cameras but not many that had weird faults or Vidicon issues beyond a burnt in image from static deployment. Maybe others on the forum will know more about what happens when a Vidicon target gets old and desensitised ? I know Vidicon tubes used to have an operational life of around 6000 hours but what effect that ‘wear’ has on the tube is not known to me. I assume sensitivity reduces over hours run and they become unacceptably insensitive at 6000 hours. The Target material may well degrade with hours run ?Regarding the auction you referenced.... that one is likely allowed as it is a listing on eBay.com. I got the impression from the warning that I received from eBay that they thought the camera should not exist outside the USA due to export restrictions so could not be listed outside eBay.com ! Weird thinking and it does not explain how international shipping is allowed on that listing. I have often received a warning about the controlled nature of thermal cameras with regard to shipping when bidding on US auctions for such. Maybe the same would occur if I bid on those cameras ? EBay’s warning puts the responsibility on the buyer to not place the seller in a position where they break U.S Regulations applicable to such equipment ! Strange but true. It would not hold up in court though ! The seller is ultimately responsible fir export and export compliance.Fraser

author: _Wim_
author_rank: Super Contributor
timestamp: October 10, 2020, 05:59:02 pm
content: I did some more testing with a printed test pattern. If I place an opaque object in front of the test pattern, I still can see the test pattern for maybe more than 20 seconds and the opaque object never really becomes fully opaque. When removing the opaque object the decay is faster (around 3 to 5 seconds).My best guess is the tube sensitivity is so low the gain is pushing too hard and the tube is constantly oversaturated. I cannot imagine this problem to be caused by anything else than the tube, because the test pattern remains clearly visible in the opaque object, and no electronic component can have this kind of "memory" effect, as the image is scanned line by line.So my best chance is like you told to check all voltages and currents going to the tube, and hope that something is wrong there. Hopefully Hamamatsu will provide the datasheet for the N2606, because the required voltages and currents from the Ikegami datasheet cannot be trusted of course.

author: _Wim_
author_rank: Super Contributor
timestamp: October 10, 2020, 06:04:31 pm
content: I used this test pattern btw:http://www.bealecorner.org/red/test-patterns/ISO_12233-reschart.pdf

author: Fraser
author_rank: Super Contributor
timestamp: October 10, 2020, 06:37:00 pm
content: This reading material may be of interesthttp://www.r-type.org/pdfs/pctdh.pdfFraser

author: _Wim_
author_rank: Super Contributor
timestamp: October 10, 2020, 06:47:35 pm
content: Quote from: Fraser on October 10, 2020, 06:37:00 pmThanks! Currently reading this one:http://6bm8.lab.free.fr/Documentations/Tubes/Vidicon%20camera%20tubes.pdfSeems extreme lag is caused by high dark current... Will read yours also. Seems like there is lots to know about these tubes, interesting!

author: Fraser
author_rank: Super Contributor
timestamp: October 10, 2020, 06:53:25 pm
content: More readinghttp://6bm8.lab.free.fr/Documentations/Tubes/Vidicon%20camera%20tubes.pdfFraser

author: Fraser
author_rank: Super Contributor
timestamp: October 10, 2020, 06:54:05 pm
content: Ha ha it is the same as the one you are readingGreat minds think alike

author: _Wim_
author_rank: Super Contributor
timestamp: October 10, 2020, 06:54:50 pm
content: Quote from: Fraser on October 10, 2020, 06:53:25 pmI think that is the one I was already reading

author: _Wim_
author_rank: Super Contributor
timestamp: October 10, 2020, 06:55:41 pm
content: Quote from: Fraser on October 10, 2020, 06:54:05 pmAnd post at the same time also...

author: Fraser
author_rank: Super Contributor
timestamp: October 10, 2020, 07:00:14 pm
content: An interesting paper on Vidicon ageing.......https://dacemirror.sci-hub.se/journal-article/be0e2b7f8628c837ae679d3f7fac1489/fafarman1968.pdfThe document seems to describe the symptom that you are seeing in your camera and it’s cause.Fraser

author: _Wim_
author_rank: Super Contributor
timestamp: October 10, 2020, 07:05:35 pm
content: Quote from: Fraser on October 10, 2020, 07:00:14 pmThat link does not work for me. Can you post the link or the original paper so I can open it in sci-hub?

author: Fraser
author_rank: Super Contributor
timestamp: October 10, 2020, 07:16:10 pm
content: Here you gohttps://ieeexplore.ieee.org/document/1475417It describes what appears to be happening in your Vidicon.Fraser

author: _Wim_
author_rank: Super Contributor
timestamp: October 10, 2020, 07:19:42 pm
content: Quote from: Fraser on October 10, 2020, 07:16:10 pmThat's not good. I was still hoping is would be an electronic problems. There seems to be a problem with sci-hub, I still get "dacemirror.sci-hub.se refused to connect."I will try again later.

author: Fraser
author_rank: Super Contributor
timestamp: October 10, 2020, 07:23:14 pm
content: I will download it and send the PDF to you. Please PM me an email address.It sounds like your tube has hit the end of its operational life and not due to Cathode poisoningFraser

author: _Wim_
author_rank: Super Contributor
timestamp: October 11, 2020, 09:36:17 am
content: This morning I lowered the target voltage from 27V to 8V, and the result is much better. Off course I need to open the aperture more (camera is now less sensitive), but in roomlight conditions I am still not with a fully open aperture (at 2.8, and lens goes to 1.4).This lowers the lag to well below 1 second, which is much more workable.VR302 was used to adjust the target voltage. So far I can say that the service manual from Ikegami matches perfectly with my camera. VR302 was turned up higher by somebody before (paint marking was broken), but now I am well below the the original position.Hopefully Hamamatsu will provide the datasheet for the N2606, so I have more of an idea what the grid voltages should be, the dark current and a ballpark target voltage number (this seems to vary from tube to tube, and from what I have read, should be adjusted in relation with dark current).I wonder is the "gain" adjustment on the 7290A is in fact target voltage adjustment. The 7290A has adjustable/auto gain, but the 7290 also has an internal jumper (J202) for ASC (automatic sensitivity control?) "on" or "off" , and this also affects the target voltage, and it could be that it is this jumper together with potmeter VR302 is brought externally to provide the adjustable/auto gain...

author: Fraser
author_rank: Super Contributor
timestamp: October 11, 2020, 10:46:35 am
content: If Hamamatsu do not provide the data sheet I will measure the various tube voltages on my 7290A camera for you. They are, of course, ‘as set’ by Electrophysics but should be a useable reference and better than nothingIf I get a chance I will measure them anyway as the information may still prove useful. I am a bit busy at the moment though.Fraser

author: _Wim_
author_rank: Super Contributor
timestamp: October 11, 2020, 11:36:03 am
content: Quote from: Fraser on October 11, 2020, 10:46:35 amMany thanks for that, but I have good hopes to receive the datasheet also.I resoldered jumper J202 to the "on" position and turned up the target voltage (VR302) to the original position. Now target voltage is automatically adjusted between zero and the max set by VR302. This allows me to fully open the aperture without saturation, and even further improves lag.Attached is the result I have filming the test image. Room lights are about 520 Lux (when lux meter is point to the ceiling), and about 200 lux (when lux meter is set next to camera lens pointing vs test image). Not the charpest, but of course this camera is not optimized for visible light I guess, and vidicon resolution is only about 600x600.Capture device was a low cost "easier cap" USB dongle.

author: _Wim_
author_rank: Super Contributor
timestamp: October 11, 2020, 11:47:44 am
content: This is the result when a black even surface is filmed. Some small burn-ins (hard to capture, is better visible when moving an object in front of the camera), but looks quite even.

author: _Wim_
author_rank: Super Contributor
timestamp: October 11, 2020, 05:45:10 pm
content: I measured the video signal with the scope, and it is a bit weak and not completely in spec. But when I try with an imaging source capture device instead of the low cost "easier cap" I get much butter results. I am currently working my way through the adjustments, but already very happy with the results so far...

author: _Wim_
author_rank: Super Contributor
timestamp: October 11, 2020, 07:48:58 pm
content: The above picture is the best I could get after the adjustments. Some adjustments did not work however:- pedastal level in video signal could not be adjusted using VR204, it is about 0.15Vpp instead of the recommended 0.1Vpp- preamp output should be 0.3Vpp, but was only 0.08Vpp- HF (VR203), LF (VR202) did not have any visible effect, so I left them in the same position- gamma, width and height I left as is for the moment- beam current is still almost at max, otherwise I do not have any output.All in all I am quite satisfied with the result. The camera is for sure usable for the moment.

author: _Wim_
author_rank: Super Contributor
timestamp: October 14, 2020, 04:43:17 pm
content: Received the datasheets for the N2606 from Hamamatsu!Typical target voltage is 40V, but at 27V I already have 20 seconds of lag. But it will be good to check everything else.

author: Fraser
author_rank: Super Contributor
timestamp: October 14, 2020, 06:37:50 pm
content: Great newsThank you for sharing the datasheetsFraser

author: DaJMasta
author_rank: Super Contributor
timestamp: December 28, 2020, 04:08:12 am
content: 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.

author: _Wim_
author_rank: Super Contributor
timestamp: December 28, 2020, 07:29:24 am
content: So your 7290 is not based on the Ikegami ITC-510? Can you post some pictures of the camera's internals?I see you also have some ghosting effects. Not as bad as mine was originally, but I think mine is now slightly better with the adjustment described here:https://www.eevblog.com/forum/thermal-imaging/swir-electrophysics-micronviewer-7290a-user-manual/msg3272196/#msg3272196

author: DaJMasta
author_rank: Super Contributor
timestamp: December 29, 2020, 07:32:00 am
content: 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.

author: _Wim_
author_rank: Super Contributor
timestamp: December 29, 2020, 08:56:40 am
content: 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.

author: Fraser
author_rank: Super Contributor
timestamp: December 29, 2020, 01:00:24 pm
content: 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 applicationsFraser

author: Fraser
author_rank: Super Contributor
timestamp: December 29, 2020, 01:11:13 pm
content: 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 situationsCompany history....http://www.fundinguniverse.com/company-histories/cohu-inc-history/Fraser

author: Fraser
author_rank: Super Contributor
timestamp: December 29, 2020, 01:37:27 pm
content: 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 diggingFraser

author: Fraser
author_rank: Super Contributor
timestamp: December 29, 2020, 01:48:10 pm
content: This SMPTE article details some new COHU product releases, including the 2800B series cameras. The article is dated 1978 so the 2800B series may be a bit early for the Electrophysics later model 7290 design.https://ieeexplore.ieee.org/stampPDF/getPDF.jsp?tp=&arnumber=7241383&ref=aHR0cHM6Ly93d3cuZ29vZ2xlLmNvbS8=COHU still looks like a sensible option for Electrophysics to use though.Fraser

author: Fraser
author_rank: Super Contributor
timestamp: December 29, 2020, 01:57:46 pm
content: The COHU 2810 camera saw service in research areas as evidenced in the link below involving target recognition analysis. The Document is stamped 1982.http://www.micro-machine-shop.com/Effects%20of%20color%20&%20contrast%20on%20target%20recognition%20performance%20using%20monochromatic%20television%20displays.%20(AFAMRL-TR-82-9)%20a116238%20%20A%20R%20Pinkus.pdfMore digging into COHU products is needed.Fraser

author: Fraser
author_rank: Super Contributor
timestamp: December 29, 2020, 02:05:19 pm
content: COHU 8120 ..... another possible basis for the the 7290 camera electronics ?

author: Fraser
author_rank: Super Contributor
timestamp: December 29, 2020, 02:32:51 pm
content: 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

author: Fraser
author_rank: Super Contributor
timestamp: December 29, 2020, 02:42:55 pm
content: 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

author: Fraser
author_rank: Super Contributor
timestamp: December 29, 2020, 02:49:25 pm
content: Electrophysics 7290A power connector identity.On a different subject, I managed to identify the 7290A power connector with the help of the forum membership some time ago. It is a Hirose product. See here....https://www.eevblog.com/forum/chat/mystery-industrial-camera-connector-help-please/It is a Hirose (HRS) connector from the SR30 serieshttps://www.hirose.com/product/en/products/SR30/Available from Radio Spares for around £12 each !Fraser

author: Fraser
author_rank: Super Contributor
timestamp: December 29, 2020, 04:42:37 pm
content: 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 assemblywhether 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

author: Fraser
author_rank: Super Contributor
timestamp: December 29, 2020, 05:08:49 pm
content: 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 identifiedIt is a COHU 5200 series cameraThe 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 chassisI wonder if a COHU 5200 series camera service manual is available somewhere on the internet, or even to purchase ?Fraser

author: Fraser
author_rank: Super Contributor
timestamp: December 29, 2020, 05:36:33 pm
content: 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 controlAlso 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

author: DaJMasta
author_rank: Super Contributor
timestamp: December 29, 2020, 06:24:14 pm
content: 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.

author: _Wim_
author_rank: Super Contributor
timestamp: December 29, 2020, 06:47:36 pm
content: Quote from: Fraser on December 29, 2020, 05:36:33 pmWe can see that!Great research and as always an interesting read.

author: Fraser
author_rank: Super Contributor
timestamp: December 29, 2020, 07:31:43 pm
content: I am sad that I cannot provide a schematic, or even a user manual howeverThe 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 assemblyFraser

author: Fraser
author_rank: Super Contributor
timestamp: December 29, 2020, 09:40:20 pm
content: 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 soonFraser

author: Fraser
author_rank: Super Contributor
timestamp: December 29, 2020, 09:52:37 pm
content: Electrophysics 7290A pictures

author: Fraser
author_rank: Super Contributor
timestamp: December 29, 2020, 09:56:53 pm
content: Pictures continued.....

author: Fraser
author_rank: Super Contributor
timestamp: December 29, 2020, 10:00:20 pm
content: Pictures continued.....

author: Fraser
author_rank: Super Contributor
timestamp: December 29, 2020, 10:06:33 pm
content: Pictures continued.....

author: _Wim_
author_rank: Super Contributor
timestamp: December 30, 2020, 05:42:00 am
content: The 7290A is really compact, my 7290 is massive compared to that! The 7290 does have a shielded preamp however, but I guess they discovered they could do without.As your 7290A has seen not much use, I would be very interested to see a short movie where you wave in front of a soldering iron or similar. This way we can see what is achievable from picture quality / speed with a almost new N2606 tube.

author: Fraser
author_rank: Super Contributor
timestamp: December 30, 2020, 11:05:46 am
content: _Wim_,I am not set up to record and upload video at the moment but will find one of my USB video capture units and sort something out for you soon.Fraser

author: Fraser
author_rank: Super Contributor
timestamp: January 03, 2021, 12:42:04 am
content: The Electrophysics 7290A is being rehomed with a good friend on this forum so it is going to a deserving home. I will be testing it, hopefully tomorrow, and will make a short video of the image lag available to those with an interest in such. At least this nice camera will now get some use rather than sitting ‘collecting dust’ in my spare roomFraser

author: Fraser
author_rank: Super Contributor
timestamp: January 04, 2021, 09:58:04 pm
content: The Electrophysics 7290A testing and videos are to be found here:https://www.eevblog.com/forum/thermal-imaging/electrophysics-micronviewer-7290a-heat-imaging-test-and-inherent-display-lag/I started a new thread for the tests to make them easier to find in the future.Fraser

author: DaJMasta
author_rank: Super Contributor
timestamp: February 04, 2021, 03:21:54 am
content: A little update on my 7290 non-A:I've put maybe 15-20 hours of runtime into the unit since my oscillator fix and initial testing, and I've been trying to maximize image quality in software by boosting contrast and reducing brightness and gamma (high black levels seem to reduce the overall dynamic range of the image). Today I got enough of my new capture setup working to give it another test, and while I'll post in the other thread when I can document it, a dedicated SD capture card does wonders for black level and visual resolution over a USB dongle, I also took off the cover again to tweak some image parameters and sure up the aspect ratio.I had noticed after my initial adjustments that on the right side there was a band at the edge that was very clearly imaging but that was darker than the main part of the image, and on the left side the edge seemed to fringe towards white output despite being within the limits that would fit in the circular aperture captured when you decrease H size and V size enough to see it. I adjusted the H size to cut off more and recentered it, then adjusted the black and white levels as well as the setup voltage to give better contrast and evenness in similarly lit conditions.It was then that I turned off my SWIR light source and noticed I could still see some image.... but in reverse. I think I've managed to burn in my tube slightly, but while I'm probably going to play with the target voltage a bit to try and adjust things, I was wondering if anyone knew if overdoing and adjustment could effect burn in. The amount is small, it's only really visible with lights off, and it's on the static elements of the frame that are reflective and fairly brightly lit. The burn in is a negative of the image captured, so I wonder if exposure to strong sources could actually help reduce the total effect - with the notable exception of a nixie clock in frame, which also has the display visible after power up and with dark over the frame, but these appear bright as if lit when no light is actually exposing the tube.In any case, it was a bit alarming to notice after such a short use, so I'm going to see what I can do to reduce any further effects. I left my target voltage and high voltage on middling settings to try and avoid issues, but perhaps they are still set too high even though I don't believe I'm achieving the voltages on the silkscreen.

author: Ultrapurple
author_rank: Super Contributor
timestamp: February 04, 2021, 11:47:17 am
content: Burn-in was a problem with visible light vidicons so I suspect it may also affect IR tubes. Most minor burns seem to sort themselves out over time (days) but some can be permanent. Back in the say I had a friend who bought a 'new' colour video camera based on vidicon technology and was dismayed on using it that there was a burned-in image of the shop window, where it had been on display all summer and showing passers-by their fizzogs on TV.I seem to recall that you can - with care - run a vidicon with abnormal voltages for a short period of time and in many cases reverse, or at least reduce, minor burn-in. Bill may know something about this, otherwise I'll have to call upon the memory of my friend who bought the dodgy camera (we're still in touch, occasionally, knocking on 40 years later).

author: Fraser
author_rank: Super Contributor
timestamp: February 04, 2021, 12:53:29 pm
content: I concur with what Ultrapurple has said. The SWIR Vidicon behaves similarly to a conventional visible light Vidicon where ‘burn-in’ is concerned.Burn-in occurs when the imaging target is illuminated with a bright scene for an extended period of time. This is usually days rather than minutes or hours. If a very bright source is left within the cameras field of view for an extended period of time, accelerated burn-in can occur.In normal use a Vidicon can be moderately overloaded at the target face and suffer temporary latent image retention. The same occurs with a bright scene that is static in the field of view for many hours. This phenomenon is not damage to the tube target, it is just image retention and the target will equalise itself when the scene is changed or the camera left running with its lens cap in place for a while. It will also correct itself over time with the camera switched off.Vidicon tubes do demand some respect in terms of exposing them to very bright energy sources but they are not as fragile as some may think. You have to work pretty hard to wreck the target in normal use. These SWIR cameras are designed to tolerate exposure to a relatively bright collimated laser beam hitting the target of the Vidicon via an appropriate ND filter and no lens. They tolerate such use without permanent burn-in.The enemy of the. Vidicon is a static scene viewed over a long period of time. The common use of Vidicon tubes in CCTV demonstrated how a scene could be burnt into the target over a period of a year. This applied to both exterior and interior static mount CCTV. It was not unusual to fit new Vidicon tubes in static CCTV cameras once the burn-in became noticeable to the users and distracting. Vidicon cameras mounted on scanning mounts that moved the camera slowly in the horizontal plane did not suffer the same burn-in effects but would suffer ‘hours run’ deterioration in the image as they were operating 24/7/365. Such was to be expected in a CCTV system that uses the technology and the viewing monitors could also suffer from burn-in if constantly viewing a static scene.I would advise against exposing the 7290A cameras tube to pronged viewing of a very intense light source without the camera moving to avoid over exposure of a defined area of the tube target. You do not need to wrap these cameras in cotton wool though ! Never be tempted to directly view an incandescent lamp of decent power, especially a halogen lamp. Such will risk damage to the target. The lens IRIS can reduce the intensity of the scene to help protect the tube but a ND filter is a better option.Fraser

author: _Wim_
author_rank: Super Contributor
timestamp: February 04, 2021, 08:36:21 pm
content: Probably a stupid question, but are you sure it is burn-in (in other words did you test with moving something in front of it in the dark scene)? I have seen the image reversal on mine by the auto-gain overdoing the target voltage to try an compensate for the darker scene.

author: DaJMasta
author_rank: Super Contributor
timestamp: February 05, 2021, 03:23:02 am
content: Fairly sure, I went through a bunch of adjustments again today and think I got things working a bit better, slightly less image lag, and a bit more even field - I see a good bit of vignetting around the edges of the image, so I was trying to reduce it a bit.Adjusting the target voltage had a pretty wide range where the image looked alright, too high increased vignetting, too low and eventually the picture drops out. I ended up a bit above previous and it is a bit faster.Adjusting the beam pot also seems to move around the center point of the vignetting - the darkest black on the camera - and you can move it back and fourth horizontally a bit. I found that very low beam levels were just no image, but there was a zone on the low side of the setting where the image appears in inverse, then a bit higher and it rights to the normal colorization.I could also adjust down the main voltage a bit and still have a good image, but I found that a bit of scan-line type of slightly off sync noise resulted in being off of the setting I eventually settled on.Good to hear about the potential time scale for burn in, I'm nowhere near that, and while I was definitely seeing the previous image after a cold boot the next day, after adjusting the settings today, I'm not really seeing the image that was there, so I think it was a combination of the long-term image retention and the gain/contrast settings being boosted and showing that last residual bit of charge.

author: Ultrapurple
author_rank: Super Contributor
timestamp: February 05, 2021, 09:07:44 am
content: I think it's worth noting that the timescale for burn-in previously noted is for a 'normal' scene. Permanent damage can be done instantaneously by a gross overload (such as directly viewing a laser beam or, as has been mentioned, pointing the camera at an incandescent lamp).

author: DaJMasta
author_rank: Super Contributor
timestamp: March 16, 2021, 05:12:15 am
content: I managed to get another one of these cameras working, this time a 7290A, and in my experiments and image tweaks have developed a basic starting procedure as well as a couple of tips/things to check if you're having image trouble on your unit. I haven't worked with any other vidicon devices, and the silkscreen labeling can be somewhat inconsistent between models, so it took more trial and error than I had expected, but I've at least got a reasonable procedure.When trying to get image out of a camera that you know is working, my first port of call is the 300V adjustment, just to verify that the 300V cap (and the various other voltages devised from the same boost converter) is biased at the right amount. This also effects the target voltage, so it's worth messing with first. Then, I measure the target voltage on the board and set the corresponding pot to 10-15V. In my limited experience these tubes will produce an image at lower voltages still, especially in the visible band, but with reduced sensitivity and it's useful to have a lower starting point to adjust later. Some cameras seem to have their tube's target voltage marked on a sticker, but this isn't always present and I've found it's not really required.From there, we want to verify basic imaging, which is basically making sure the tube is actually reading out usable information. When powered up, the camera should spike slightly, then gradually decrease current usage after the high voltage biasing is charged up. The screen will go white after generating the sync signal, then dark (or potentially reverse) and in a few seconds the screen will sort of fade into an image after that point, usually in a sort of spreading puddle shape and sometimes including some wavy horizontal lines (more on that later). The 7290 (non A) I have takes longer to start the image fading in, but this could very well be due to aging components, as it actually takes my 7290 a couple of minutes to stabilize at full image size/correct rotation/no flickering - I just haven't bothered to track down the responsible components. The 7290A I just worked on will get an image in less than 10s from power on, but it goes through the full screen cycles then fades into the image, even with a well illuminated scene.From the starting target voltage set, I adjust the black level pot (if the lens is facing towards you, it is the second to top potentiometer facing upwards on the left hand board) so that it is an in-between setting, then I adjust the potentiometer on the vidicon base's board (the one on the left side of the board when both pots are facing up and the lens is pointing towards you) and test to see if I can see motion in the image. Once you see motion, it's all about trying to maximize that signal, this usually involves some turning down the black level to be darker, but also turning up the target voltage slowly. More target voltage means more sensitivity and less ghosting, but too much will make the image go fully white and then, if pushed farther, fully black, and running too high can damage the tube. I like to start low and gradually increase the level until I can notice the image ghosting decrease - there seems to be a region where a little increase in voltage makes a notable change, and at a point it stops being noticeable. It is important to mention that light will leak in from the sides and you want to be setting this level as close as you can to usage conditions, so inserting the filter holder (to block some stray light) or just turning off bench lights to work with a minimum to see the adjustment pots can be quite helpful. If you're looking for SWIR or NIR only bands, it's also worth putting in that filter, so that if your target is brightly lit in visible, you don't end up setting the brightness too low in the band of interest. It is best to do these adjustments with the lens mounted and with a target that is high contrast.Once you have good contrast on your image, you want to focus it, using the focus pot on the right hand board and the pot on the right hand side of the tube base board (again with the lens pointing towards you). I try to focus the lens as sharp as I can get, then adjust the focus pot to as sharp as I can get, then treat the right pot on the tube base board as a fine adjustment for it, since it has some similar effect on the image. This usually has to be repeated, and don't worry if the image isn't plumb. At this point I move to the horizontal and vertical adjustments on the right hand board to both try and center the image in the lens aperture (you can see the circular edges when the deflections are maxed), fill as much of the aperture as possible, and stay away from any bright or dark spots that track with the movement of the position adjustments. Remember that with the image persistence it takes a few seconds for the image to settle, so it's best to adjust, wait a second, then check, rather than try to operate in realtime.At this point I turn to the four pots that are outward facing on the left hand board and adjust them for as even a field illumination as possible. Proper adjustment of these should cancel almost all vignetting at edges or bright/dark regions of the screen, and you can usually adjust them by watching the bright band or dark spot move around on the image and just try to null it out. At this point if your image is off the vertical axis, loosen the four small set screws that are holding the metal sleeve around the tube and gently rotate the tube in the required direction. This is best done in small increments, while power is off, and then repower and wait for the image to check your work. No need to be sticking your hands on the tube when it's biased at a few hundred voltages and the whole assembly is pretty sensitive to vibration and EM noise (coupled in by your hands, metallic tools, whatever). That basic process takes a bit of time, but has yielded good results for my image quality and can be started basically with unknown settings.Now a couple of quirks of the design that I've realized and which could be helpful:First off, if you have your basic voltages set, you think the electronics and tube work, but are seeing no image (and not the normal dark and white transitions that then fade into an image on power up), your tube could be the wrong distance from the lens mount. Basically, the glass tube itself can move inside the metal sleeve with the deflection coils that is anchored in place, and if the tube face is too close to the lens, it will be far enough outside of the coils for no image to appear. You can gently press on the face of the tube with a clean cloth to slowly press it farther in - in my case a millimeter or two behind the metal bracket that retains the filter mount - to make the tube set back farther in the coils, and this should get your image. Distance to the lens also effects where it can focus so it's worth testing the full range of the lens to find a good place for it, but if you need to reverse the direction and move the tube towards the lens, gently press and rotate the board on the back of the tube. The direction of rotation is not important because the image will be aligned from the coils around the tube, but turning it too far could cause access issues for the cables or to the pots.Another thing to be on the lookout for: if you see wavy horizontal lines that look vaguely like scalloped cracks... these are not cracks. I haven't actually figured out what they are, but I've now seen two tubes that with more adjustment (and some of this is tube position in the coil dependent), even when these lines are visible at the first power on image, they go away and the image can look normal. An artifact of the scanning, I think, maybe someone can shed some light on the phenomenon.Finally, the image is read off the tube through the light blue wire at the front left of the tube, into a SMD JFET on the inside face of that left board. Getting your hand or tools near that cable will couple in noise that is visible on screen, and leaving the screw out of the nearest mounting hole can cause grounding issues that give you a lot of garbage on screen.I've got another 7290A to work on that's just not able to run its boost converter for more than about 2 seconds for some reason, but I hope to test out the adjustment method again on it, which has basically the same parts and layout, but earlier board revisions with several alterations not seen in the unit I've now got working. Expect to see a comparison with the 7290 (non A) at some point too, the 7290A definitely has less of a vignetting effect, but it also could be the age/condition of the electronics.

author: Fraser
author_rank: Super Contributor
timestamp: March 16, 2021, 11:20:51 am
content: Excellent work 👍The Vidicon tube is an orientation sensitive device with regard to its installation in the deflection coil assembly. From memory the data sheets provide details.Fraser

author: _Wim_
author_rank: Super Contributor
timestamp: March 16, 2021, 06:37:11 pm
content: Quote from: DaJMasta on March 16, 2021, 05:12:15 amWow, thanks for this very detailed description!My 7290 (non-A) starts up in approx. 15 seconds, so a couple of minutes start-up is indeed probably related to some aged capacitors somewhere on the board.

author: DaJMasta
author_rank: Super Contributor
timestamp: March 16, 2021, 08:31:37 pm
content: I maybe should record the turn on sequence... it's really something. The image starts too small at the center of the screen and twisted, and gradually extends and untwists until it's full size. There's also an intermittent flicker that looks like the picture losing lock or something that is every few seconds right at the first image being displayed, but which works itself entirely out after a couple minutes powered on.Now that I'm thinking of it, that's a very similar initial behavior to the function of the focus adjust pot, so maybe it's a capacitor or something on that line or something that doesn't work as intended until it's warmed up.

author: _Wim_
author_rank: Super Contributor
timestamp: March 17, 2021, 06:54:56 pm
content: Quote from: DaJMasta on March 16, 2021, 08:31:37 pmYou know we all love pictures and video's...

author: pnsl
author_rank: Newbie
timestamp: July 19, 2021, 09:56:06 am
content: Hi, does anyone know what is the voltage for the power supply of Electrophysics 7290(non-A) version? I have one that has the exact same board as in the figure in Reply#78 but without the power supply. I assume it is AC as it has a bridge rectifier BR805D? Thanks in advance!

author: DaJMasta
author_rank: Super Contributor
timestamp: July 19, 2021, 03:04:42 pm
content: I believe it will run on 12VAC, but give it 12VDC and it should be fine. Mine runs on 12VDC from the power connector, around 10W in total. We believe the rectifer was for a version of this camera that may have had a different application or tube, and I think it would be still possible to supply it from AC (at least connecting directly to the board) given the rectifier.

author: Ben321
author_rank: Frequent Contributor
timestamp: July 19, 2021, 08:59:19 pm
content: Quote from: Fraser on December 17, 2018, 02:55:11 pmI know this is an old post, but I have a request directly related to that post. Could you possibly scan that manual and post a PDF of it here?

author: Fraser
author_rank: Super Contributor
timestamp: July 19, 2021, 09:08:21 pm
content: OK

author: Ben321
author_rank: Frequent Contributor
timestamp: July 27, 2021, 01:53:18 am
content: Thanks. I downloaded it now.

author: hap2001
author_rank: Regular Contributor
timestamp: January 13, 2023, 11:20:44 am
content: In the document I see the gamma is 0.7, is it possible to set it to the normal 0.45?