Not so usefull when one bulb is blown on one sys, and another one on the other sys!!!
Splat, in the company I work for they fix existing defects from time to time. Both systems are checked on the daily & bulbs changed then so at the start of the day both systems are working OK.
I've got a few hours on type now but have never yet discovered 2 systems with faulty bulbs. Doesn't mean it can't happen though.
