AGEMA Thermovision 480 MWIR camera (Scanner 487 & CU 480) - Page 1
Forum section: electronics / general

author: Cat
author_rank: Regular Contributor
timestamp: October 03, 2020, 01:37:25 pm
content: Finally got a MWIR camera, the AGEMA Thermovision 480This post is just a small preview, the camera is working but needs some maintenance.This thread will be continuously updated.The complete deviceThe 487 MWIR scanner camera (2-5µm, 140 lines, 100 elements/line, 20Hz) with 20° lens including motorized focus.The control unit CU 480 which can be connected to the model 478 (MWIR), 488 (LWIR LN² cooled), or 489 (LWIR, stirling cooled) scanner cameras. The LCD can be used outside with the sun shield and the angle is adjustable.Some thermal images, the sensitivity is amazing.The device is from the heir of an AGEMA salesman and was probably build in 1994.The last 26 years did show no mercy and some maintenance is required:As you can see the sheath of the cable between the scanner and control unit got brittle and needs to be replaced.The power supply is consuming 80 W when the device is running, probably half of this is wasted as heat in the linear regulator. The power supply will get an other transformer or gets replaced by a SMPS.The control unit needs to be checked, something is rattling inside and the RTC battery is dead.Probably more...Of course I already have some questions.Are there any known common problems like failing EPROMs, leaky SMD electrolytic capacitors orfailing foam coupling of the polygon mirror?Some posts indicate the optical path and scan mirrors are in vacuum, is this true?Because the bearing sounds a bit worn out, how long does it take usually for the polygon mirror to spin up & down?The manuals can be found here:Manual from 1992 including the 488 LN² cooled scanner:https://support.flir.com/DocDownload/Assets/dl/1557625$a.pdfNewer Manual from 1994:https://support.flir.com/DocDownload/Assets/dl/1557623$a.pdf

author: Fraser
author_rank: Super Contributor
timestamp: October 03, 2020, 04:41:48 pm
content: It is not a bad purchase as it works ! That is always a good start.The adhesive that holds the rotary mirror foam ‘donut’ in the coupler is prone to becoming powder and failing. The same adhesive is used in the anti vibration damper in the motor mount and also fails. I have seen this on two AGEMA 4xx series cameras that I have worked on. It is not surprising due to the age of these units.The scanner unit in these cameras is NOT in a vacuum. The earlier thermal scanner units were housed in a vacuum to improve the resonant mirror galvanometer performance by removing air resistance to the mirror movement.The rotary mirror normally sounds quite loud and ‘dry’ but this is normal for these cameras. You cannot replace the mirror bearing without risking the mirror that is very easily scratched and corroded polished aluminium. It is unlikely that the bearing has failed or is in need of replacement.The RTC battery is an AA size Lithium Thionyl Chloride cell.Take a look at my AGEMA 450 repair post as the camera you have uses basically the same scanner head. Your camera is very similar to the AGEMA Thermovision 870.Fraser

author: Cat
author_rank: Regular Contributor
timestamp: October 03, 2020, 09:56:58 pm
content: Fraser, thank you very much for sharing your knowledgeDo you have a link to your repair post? Unfortunately I couldn't find it.The scanner will be checked next, I just peeked into the control unit.To check what was rattling inside the control unit I opened the bottom first.Indeed there is a screw with a washer sticking to the adhesive tapeThe screw is from the missing strap mount (?) on the outside.The tape did a good job securing the screw, the culprit of the rattling was a piece of cut wire or shielding.A quick look onto the LCD adjustment mechanism before opening the top cover. The lever is used to lock the LCD position.With the top cover removed you can easily find the white RTC battery. It is a SAFT LS14500, manufactured 1997 and completely dead wit 0V. It has two solder pins on the positive and one pin on the negative terminal.The floppy drive is a Mitsubishi MF355S-215MG with a 26pin connector. So unfortunately there is no drop in USB floppy emulator

author: Fraser
author_rank: Super Contributor
timestamp: October 03, 2020, 11:15:50 pm
content: Hmmm I may have been wrong about posting the teardown of the THV450 and 470 cameras. I did a Teardown on the THV900 and there was little interest in it on the forum so I think I only shared the pictures and commentary privately with Ultrapurple who owned the THV450 that I was repairing. I do not think I had the incentive to document the THV4xx series on the forum at that time so it just never happened.Fraser

author: Cat
author_rank: Regular Contributor
timestamp: October 03, 2020, 11:58:20 pm
content: Quote from: Fraser on October 03, 2020, 11:15:50 pmI should probably have replied toyour post here, it would be great if you could share the teardown picturesI see this forum as an archive and I'm reading probably 98% of the time, so if you post something you can be shure I'll read it.

author: Fraser
author_rank: Super Contributor
timestamp: October 04, 2020, 11:21:42 am
content: I will find the images in my archive and upload them to a separate post to avoid confusion with your model in this thread. The THV450 and 470 are basically the THV870 scanning camera head grafted into a chassis that holds the PCB’s normally found in a separate controller unit. Hence the huge size of the THV450/470. Your unit is a variant of the THV870 as well. I may have useful spare parts from my THV470 Teardown as I decommissioned that camera due to corrosion on the aluminium mirrors. I will check which lens I have in case it is of interest. Much of the scanner head related mechanics and electronics will be the same as in your unit and the controller section uses plug in cards that may be the same PCB’s and chipset as your controller. I will check.For information, damp storage conditions are the enemy of these cameras. The lenses and mirrors do not respond well to moisture over a prolonged period of time. Interestingly, had the optical block been in a vacuum, as in earlier designs, my THV470 would not have suffered the corrosion of the mirrors. The AR coating on the lenses is very prone to lifting and flaking away on this generation of camera. This is not always due to damp storage and may just be an age related degradation in the AR layer and its bond to the Germanium lens elements.Fraser

author: Fraser
author_rank: Super Contributor
timestamp: October 04, 2020, 11:37:04 am
content: I just studied your controller and it looks likely that your camera system is basically a THV470 with the controller separated from the scanner head. Or more accurately, the THV470 is your system with the controller integrated into a chassis mounted on the rear of the scanner head. Your system looks very nice indeed. A good findFraser

author: Fraser
author_rank: Super Contributor
timestamp: October 04, 2020, 11:44:56 am
content: This 40 degree lens should fit your camera (but check the part number before buying). It is at a very reasonable price in the USA but the seller ships internationally at low costhttps://www.ebay.co.uk/itm/Agema-Thermovision-IR-Lens-40-Degree-SW-556-192-903-w-pouch-case-Guaranteed/123736287266?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D225075%26meid%3Dbe384f6226fc4ff5bdcccfe2b0385c26%26pid%3D100675%26rk%3D1%26rkt%3D15%26mehot%3Dnone%26sd%3D123736287266%26itm%3D123736287266%26pmt%3D0%26noa%3D1%26pg%3D2380057&_trksid=p2380057.c100675.m4236&_trkparms=pageci%3Aba4a3c60-0636-11eb-9e95-a68fddbdf579%7Cparentrq%3Af36be5bf1740aa19c8928ac0ffebdeb8%7Ciid%3A1Fraser

author: Cat
author_rank: Regular Contributor
timestamp: October 07, 2020, 08:45:53 pm
content: A quick update, the floppy is broken (probably the belt to drive the disk) but I "repaired" the cable.This is how it looked before, the outer sheath is mostly gone and the shielding is damaged.The cable is probably custom made, it includes conductors of different sizes as well as two shielded coaxial cables.The good thing is it's a 1:1 extension and has male and female DB-25 connector.The connector has crimped contacts which can be inserted and extracted with a special tool. I used a 1.8mm blunt dispensing needle and modified it a bit, works perfectly. Isopropyl alcohol can be used as lube to aid the extraction process.Here you can find a description how to insert and extract the pins, much better than I could dohttp://www.aeroelectric.com/articles/D-Sub_Pin/Pin-Extraction.htmlandWith all the pins removed some heatshrink helped to keep the pins tightly together.The replacement sheath is 12.8mm heatshrink which has to go over the shielding. A few sprays of silicone oil helped to slide the heatshrink over the shielding braid.After everythig was in place the new sheath was shrinked. It's not as nice as a new cable but it's doing its job.Now the pins can be put back in the connector.The finished cable with new thumbscrews.

author: Bill W
author_rank: Super Contributor
timestamp: October 07, 2020, 09:01:26 pm
content: Would not argue with c 1994, I recognise many of those PCB components as ones I put in the Argus 1Bill

author: Fraser
author_rank: Super Contributor
timestamp: October 07, 2020, 10:08:26 pm
content: I can recommend PMA Polyamide or PET expandable braided sleeving for umbilical cables. It is hard wearing, very flexible and has the advantage of expanding in diameter when compressed, for ease of installation. You can select a diameter slightly smaller than the cable for a tight fit and relatively rigid cable, or go for a diameter larger than the cable to achieve a nice loose fit and great flexibility. It is like a snake skin and really good in such applications. Radio Spares used to do it in 5m lengths for sensible money rather than having to buy a 100m reel. It may be worth searching eBay for a deal on some of this PMA braided sleeving or there is a nylon version in grey.I tend to use 15mm diameter braided sleeve for my umbilical cables. RS sell this here at reasonable cost...... RS 408-205 (5m length)https://uk.rs-online.com/web/p/cable-sleeves/0408205/Fraser