Tascam 688 grp master pcb 52102860-01 This block is slightly taller

This block is slightly taller than the standard that was used a long time then and after as they had the 4 switches mounted above it and head block had to allow for that

reversing motors marked CW CCW have a different bush contact

This maybe a common board in other units but listed like this

but if you have just a whole there now these are a whole lot better

Tascam 688 grp master pcb 52102860-01 This block is slightly tallerBoard 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