I do have a bit of a penchant for Technics gear of this era. Once fixed it looks and sounds very nice. For the most part, Technics items are quite serviceable, although I'll admit to a few notable exceptions. I ended up making a few extension cables for this one and sitting the entire control board and pu arm control pcb's on a bit of vinyl flooring on the top of the deck. I was then able to fault find without adding any more faults
I have had an odd 4013 logic chip fail before in the speed display circuit, but the arm control has normally being fine. I sure someone had an accident during fault finding on this - hence the extensive number of failures.
At least all the 4000 series Ic's are cheap. If it had been a specially masked micro, it would probably have been game over.
Regards SJM.