Another look at the hours meter and I am starting to doubt that it is working. The bubble is so far off the left mark of the scale that it just does not look right. I think I will ignore that meters indication. I enjoy investigating the history and failure of thermal cameras but I believe this one will be a simple case of "Years Vs the Stirling Cooler".
Would I recommend anyone buy one of these older Sterling cooled scanning type cameras to use and expecting a good few years life out of it? In short no, these cameras were great in their day, but the poor Cooler is long past its best. Hours run and any Helium leakage place the odds against such a camera lasting very long in service.
The Peltier cooled scanning cameras like the AGEMA Thermovision 450, 470 and 480 are more likely to give reasonable service as the only gas related concern is the quality of the vacuum in the Vacuum Dewar around the detector die. That vacuum is often very long lived, just as in Thermionic Vacuum Tubes.
Fraser