MECHA CONT PCB 52102762-00 Often these get dusty and

Often these get dusty and then people store them in a damp place and they corrode

I am not sure if its because a bigger shaft fits over this or it was designed for a different speed as the numbers don't match up

Nice standard size heatsink black anodised with a 2SD797 mounted on it used for controlling power to the motors

this one is 41cm long

MECHA CONT PCB 52102762-00 Often these get dusty andBoard from a 688 and maybe common in some others The 688 was really the flagship analogue portastudio amazing what the could get on 1 8 inch tape I was amazed how heavy and how big the machine was must be 15 kilos maybe, Nearly all the boards inside are with connectors so its one that can be serviced easier