At the end of last year we had the embarrassing situation of giving a demonstration on the simulator and the mains supply RCD tripped. Caused by leakage current somewhere, but where? Top of the suspect list was a power supply and to find out meant an elimination process. Usually it’s straight forward as a defective power supply usually emits smoke as a capacitor’s dielectric boils. No smoke so a start was made by disconnecting different banks of power supplies in turn. After a while the well-recognised hot dielectric smell was emitting from the console and it’s not easy to access these power supplies as seen below.
The bubble wrap is to catch any screw that tries to drop into the works!
All three of the power supplies in the console were removed for a filter capacitor change. Unfortunately the RCD still tripped with the console supplies removed! Elimination continued and eventually the culprit was found. The RCD trips being cause by the bottom right power supply.
All remaining time on this work visit was spent on coating previous cleaned lamps, knobs and switches in the LCP with Polytrol. Well worth the effort as sown off here.