Just to let everyone know, I have now fixed this PSU. The final write up is here:
https://robs-old-computers.com/2017/10/01/decstation-5000-model-240-psu-fixed/ Thanks everyone for all the help. Now back to the DECstation 220, a ZX Spectrum, and then the daunting task of fixing the TURBOchannel Extender I got for this thing. Regards Rob
