i was thinking that as well.
Clients board with clients rom - drive doesnt power.
Donor board with donor rom - drive clicks constant 'tick tick tick tick'
donor board with client rom - drive clicks, power cycle, clicks, power cycle.
because the heads acted differently each time i was hoping it was PCB incompatibility rather than heads. but then with all WD drives in the past, a ROM swap has allowed me to access data.
I may as well swap that component over anyway and see what happens, unless anyone tells me not to in the next few minutes

in case i cause a rip in space time or something.