I worked on that exact model during a locum at Riyadh Military Hospital in SA,they showed it me working but when they switched it on and were preparing to put a patient on there were no alarms showing behind the black plastic panel and said there never had been,I quickly took the cover off and wiggled a large relay and it lit up like a Christmas tree.
Just proved how intrinsically safe they were as they had been using it for years oblivious :-)
www.healthtec.co.uk