Well No. 1 was the original. No. 2 was a replacement sent to me when I originally purchased the equipment. The Crypton machine had many faults from new. The sensor was sent out but the technician never used it. Therefore, although around 4 years old, it was still packaged and as new.
No. 3 sensor, I have just bought.
Getting the sensor to room temp. seems worth trying.
As for re-connecting everything. I have done it, but will try it again. I am now thinking that the programme itself needs reinstalling. Maybe it has become corrupt somehow?
Any ideas which disc I would use? It might be one of the floppy discs I have? I am now concerned about messing up the whole programme!