So I ended up purchasing a second hand MD600 and am back up and running. Interestingly, the power LED is much brighter than on the disabled unit which does make me wonder if it’s a power supply issue. I shall be sending it out to Marc Koval. If they can fix it then I have a spare.

My Kit: 861v8+ID41, 800v4, UHD722, MD600, MS600, MS200, Oppo BDP-203, Genesis 201, Genesis 350 SE, Genesis S4-8 Sub, BG 520i, VTL MB450 II, Krell Showcase 7, Genesis 928 Subs, Danley DTS10 sub, SVS Ultra 16 subs.