Flir Prism SP - Page 1
Forum section: electronics / general

author: somlai gabor
author_rank: Newbie
timestamp: June 10, 2023, 10:06:28 pm
content: Dear Friends,I'm working on a Flir Prism SP imager. . This camera was working fine and the next time it didn't turn on. The camera gets power, but the cooler won't make the usual noise. I changed all the capacitors on the main board hoewer they tested fine. I'm suspecting the cooler but I would like to make sure that the two DC to DC converters are working, so I unsoldered them but I don't know the input and output legs dedications. I believe if I see voltages they probably working fine This is where I need help to tell me the 12 Volt input legs locations . Thanks

author: Fraser
author_rank: Super Contributor
timestamp: June 11, 2023, 12:26:23 am
content: Here you go..... datasheets attachedOriginal CDI data sheet with testing protocol is available here:https://www.digchip.com/datasheets/download_datasheet.php?id=11587&part-number=1605%2F12T12Fraser

author: Fraser
author_rank: Super Contributor
timestamp: June 11, 2023, 12:40:44 am
content: Can you describe the change in the coolers sound as that may be something I can help with. I have worked on quite a few cooled cameras and know when they sound 'sick'. Failure modes are usually loss of gas (runs at maximum speed for ever!) or mechanical failure (sounds like something is loose inside making lots of noise and vibration). Coolers are often on their own self contained control circuit and can often run when a fault exists on the cameras microprocessor system. They will cool and drop into the slower maintain' state without intervention from, or need for, the main processor board. A camera that boots properly and runs in all respects, except the cooler sound is wrong, may have a fault in the motor driver for the cooler as it is two speed. A camera that does not boot, yet the cooler runs, is normally suffering from a fault not associated with the cooler. You are right to check power rails as a failed power rail could impact the cooler motor controller.Fraser

author: somlai gabor
author_rank: Newbie
timestamp: June 11, 2023, 02:04:58 am
content: Hi Fraser,The camera was working fine just before I wanted to sell it, and here is a link for the video when it was running fine. It cooled down in under 5.00 minutes and the FSI screen always came up and it was ready to go."https://youtu.be/ZsiRjsYq1Wg" The next time I powered it on, there was a fan noise only but not the regular pump noise, and it was never booted to the FSI screen. Thanks for the CDI testing protocol, I was looking it for it all over with no luck. I have more pictures from this project but the file are too big to post. I could post one or two at one time, maybe. The English is my second language so sorry about the grammar.

author: Fraser
author_rank: Super Contributor
timestamp: June 11, 2023, 10:18:29 am
content: A 5 minute cooling down period is excellentThat does not sound like a cooler that was nearing ‘end of life’.The symptoms do suggest a power related issue. It could be a power rail control problem or shorted power rail causing an over current event. The power supplies may all be present but just not being allowed to reach the systems within the camera. As well as the actual DC-DC modules you will need to check for expected voltages on various parts of the camera. The cooler is clearly not running so power is not being provided to its motor driver. The microprocessor board needs to be checked for its power rails and you need to look for MOSFET power rail control points and check those. In this age of camera it is not unusual for them to suffer power rail related capacitor failures.Tantalum capacitors are especially troublesome and can go virtually short circuit or burn up !Best of Luck with the repair. I do not have an FSI Prism in my collection so if it cannot be repaired and you wish to sell it, let me knowFraser

author: somlai gabor
author_rank: Newbie
timestamp: June 11, 2023, 02:09:15 pm
content: I wonder if I could apply voltage directly to the pump motor to test if it is starting up. It is a two wire connection, probably 12vdc.

author: Fraser
author_rank: Super Contributor
timestamp: June 11, 2023, 02:59:56 pm
content: No, do not attempt to apply DC to those wires. The cooler uses a twin linear piston system that is basically a dual piston assembly in a sleeve that is surrounded by a field coil. The field coil is fed with an AC drive signal of the correct frequency to cause efficient operation of the pistons against their springs. The pistons are operated in a resonant mode determined by the spring design. This makes them more power efficient.If you apply DC to the field coil, it will cook and the pistons will not oscillate.Fraser

author: Fraser
author_rank: Super Contributor
timestamp: June 11, 2023, 03:12:05 pm
content: You need to ignore the cooler for now. If the camera is not showing signs of life by creating a display on its viewfinder or video output, you have a problem not associated with the cooler driver, unless a short circuit has appeared on its AC driver or controller supply rails. Linear coolers are VERY reliable.Fraser

author: somlai gabor
author_rank: Newbie
timestamp: June 11, 2023, 04:34:43 pm
content: I will solder the two DC converters back and see if the voltage get there at all and measure in/outputThanks