Subject: 1270C Modification For THENET EPROMs

To  modify  the  MFJ-1270C  for  use  with  X1J/Thenet  EPROMS follow these
instructions:

You  must  complete  all  of  these  steps  in order for Netrom firmware to
function.

NOTE:  if  you are not using X1J firmware skip the first step and make sure
       that JP15 is set for 256k.

Step  1:  Bend pin 1 of 27c512 out so it will not touch socket, then jumper
          pin 1 of 27c512 to pin 8 of MODEM header J4. (see X1J docs)

Step  2:  Remove U40. Add jumper from pin 16 to pin 10 (ground pin 16)

Step  3:  Remove JMP9 altogether  (no jumper on any pins)

Step  4:  Cut JMPX "PAD" to prevent node from hearing itself

Step  5:  Add 100ohm resistors to R14 and R15 if not already in place.

Barry Hoobler WB7AHN.#SWOR.OR.USA.NOAM

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