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 bonus
I 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