Thanks for the prompt and comprehensive reply. No, there is no video output. that is one of the first things I checked and which made me suspect that the fault was not with the EVF. There seems to be intermittent lockup , as sometimes I can switch on and off OK, but sometimes I can't. Usually after I have been probing around on the boards, so probably due to my probing, as the system restores if I remove the power and reconnect it.
There is little I can do without knowledge of the boards circuitry and I am certainly not in a position to do any reverse engineering, although I have had a look at some of data sheets and examined the boards for any obvious damage..
I wish you luck with your clear out, I've been trying to clear my garage for over ten years and it is still bulging with unwanted equipment and old household stuff. If you ever reach the state when you can take a look at our PM675, then let me know, as it will still be sitting here unrepaired. We would, of course, expect you to charge for the repair, or even for examining it, but I guess it would still be cheaper than sending it to Flir and with the added attraction that I think you would let me know what you have found and how you have repaired it, which is more than I would get out of Flir.
You are not far from us, as we are located just outside Cambridge.
Sid