Thermal Imager Failure Modes - Page 1
Forum section: electronics / general

author: falcom
author_rank: Contributor
timestamp: March 08, 2018, 01:52:05 am
content: I at a total loss to find info about failure modes. i have several thermal cameras/cores that have problems. I am not sure how to troubleshoot since I am not sure whee the problem begins. For example I have one camera that displays an image but has a shaded area in the corner. After it has been on for several minutes the image begins to degrade and become more pixilated.Another camera only displays a white screen (white hot) or black depending on polarity. The menu comes on and it tries to calibrate but no image appears.Are theses sensor problems or are they at the processing level?ThanksDave

author: Spirit532
author_rank: Frequent Contributor
timestamp: March 08, 2018, 02:08:19 am
content: Quote from: falcom on March 08, 2018, 01:52:05 amSounds like the camera wants to do a NUC badly but can't. VOx microbolometers do need NUC. Sensor may also be damaged or the NUC shutter is stuck mid-cycle, giving that shaded corner.Quote from: falcom on March 08, 2018, 01:52:05 amCan be anything from a dead power supply rail to a cooked sensor. Needs a lot more information.

author: falcom
author_rank: Contributor
timestamp: March 08, 2018, 02:51:37 am
content: Thanks I will look for the stuck shutter.EDIT Stuck Shutter It IsOn camera 2 I dont even know where to start looking.

author: Chanc3
author_rank: Frequent Contributor
timestamp: March 08, 2018, 07:06:12 am
content: Quote from: falcom on March 08, 2018, 02:51:37 amTbh this also sounds like a stuck shutter - just it has been stuck in the down position, so you only see the one uniform image.

author: Fraser
author_rank: Super Contributor
timestamp: March 08, 2018, 02:45:32 pm
content: Sadly information on common failures in thermal cameras is limited as not many people specialise in repairing them. Those that do, tend to stay quiet about the common faults and diagnostics methodology as they are trying to protect their income stream. Thermal cameras remain quite a specialist product when it comes to finding a repair house that will carry out the required diagnostics etc.This excellent sub forum is likely the best place on the internet for assistance with fault finding on thermal cameras. I do a lot of repairs and restorations and do try to help others in need. I will admit to being careful how much detailed information I share as I do make a small income from my hobby. There is also the prickly subject of technology information restrictions. In some cases I cannot publish my technical notes or knowledge on a public forum as it might get the attention of parties that prefer such to remain out of the public domain. I am not looking for trouble !There are a number of books that provide excellent detail on how thermal imaging cameras work and ULIS released some very interesting documents from seminars that detail how the microbolometer array and ROIC works. It is possible to gain a generic knowledge of thermal camera design and operation from publicly available documents and books. Sadly, camera specific information is very hard to obtain for all manner of reasons. I learnt much from actually working on many thermal cameras and reverse engineering them. I actually purchased faulty cameras with the sole objective of learning how they worked and if I repaired them, it was a bonusI met a brick wall with many manufacturers when enquiringly about the most basic of technical detail on obsolete cameras. Only one OEM was helpful and I owe a debt of gratitude to their staff who helped me to better understand some technical aspects of the thermal camera design process. This still had to be done within the constraints of technology regulations and NDA restrictions though.When looking at a new patient I have an inspection process that I tend to follow. I think I previously detaile it on this forum. The power supply circuits are always high on the inspection list, along with any parts that move ! The FFC flag can become intermittent or jammed as it is fragile and regularly moving whilst the camera is in use.Well I hope that explains your difficulty in gaining technical guidance on thermal camera repair. You are amongst some very knowledgeable and friendly people in this forum so I hope you get the help you need.Fraser

author: falcom
author_rank: Contributor
timestamp: March 08, 2018, 06:33:57 pm
content: Fraser,Any suggested books or links to documents?Dave

author: Fraser
author_rank: Super Contributor
timestamp: March 09, 2018, 12:26:27 am
content: Sorry, I have no access to links..... I found documents over many months and just downloaded those of interest. As to books, I did list them in a post on thermal imaging learning materials. I will see if I can find it.Be warned, books on thermal imaging are considered somewhat specialist and somattract eye watering prices, even when used. £50 is about the minimum for several that I have.Fraser

author: Fraser
author_rank: Super Contributor
timestamp: March 09, 2018, 12:31:25 am
content: Well I did not find my book list yet but I did find my post detailing free on line educational material that may be of interest.https://www.eevblog.com/forum/thermal-imaging/free-thermography-and-camera-use-guides-books-the-list-)/msg1220186/#msg1220186Fraser

author: Fraser
author_rank: Super Contributor
timestamp: March 09, 2018, 01:12:27 am
content: Nope, can't find the book list I posted. I will have to look at the books and post details over the weekend. Sadly, as stated, they are rare and/or expensive.Fraser