Thanks, Fraser! It came from a FC-309S security camera. That was actually the reason for disassembly in the past - replace whatever web interface board it came with with the VPC board it uses now plus replacing the lens holder in front (both original Flir parts I got from eBay). Remember admiring how well it was built when I opened it, must have jinxed it (could also static have zapped the sensor or something?) Otherwise this unit hasn't been abused, I do take care of my stuff (it was also supposedly refurbished by Flir before coming to me).
I did take apart and put back together again yesterday. Don't like that fat rigid ribbon cable from the sensor board, too rigid for the angle it's bent under. It does go in, but can't be 100% sure everything reliably connects. Tried using its original security camera interface with the same result - digital communication fine, video test pattern fine, no image. Edit: I did wave hot things in front of it too - it doesn't register.
Where do I get the sensor pin layout from? I do find the Tau teardown thread here, but I only noticed a block diagram or something?
Thanks again...