OKAY I have a WORD Doc that I made up from one of the Tape Project forum. I will say one thing before you read the following: I would take the leads off the head block plug and move the wires I disconnected to a pair of RCA sockets on the rear of the machine perhaps above the inputs. This is so you can take the wires going to your outboard preamp and plug them into he original deck's electronics to return it to it original state if desired. Here's a copy and paste: Otari MX-5050-BII-2 tape head output modification:
These instructions assume the reader has the service manual for the Otari. My copy is Edition 8 dated October 1987.
Referring to the view in Figure 5-1 on page 5-2 lay the unit on its back, remove eight screws to remove the bottom plate and pull down the bottom panel providing access to the amplifier board, A10620B foldout, following page 10-1.
Using the circuit board diagram PB-16EB on page 8-3, locate terminal blocks 9, 13 and 14. They are numbered on the blocks. The pin numbers are located on the board next to the PCB-mounted male connectors. Note these numbers. Loosen the screw that attaches a ground wire at the right end of the chassis. Block 9 is the channel 1 and channel 2 connections from the heads. (follow these wires up to the head connections) Pin 4 is channel 1+, pin 1 is channel 2+, pins 2 and 3 are grounds.
Hope this helps.
