MFJ-1270
MODS
RESET CIRCUIT
If
power drop outs confuse or locks up your TNC, try
replacing the reset capacitors.
Replace
C-58 [1 uF] tantalum
Replace
C-22 [10 uF] tantalum
# 5 on to computer comm
port 9600b
# 7 on radio baud rate 1200b
JMP
1 OFF
JMP 11, RIGHT
JMP
2, 1 TO 2 JMP 13, ON
JMP
4, OFF
JMP 15, 1 TO 2
JMP
5, OFF
JMP 18, 1 TO 2
JMP
7, OFF
JMP 26, 1 TO 2
JMP
8, ON
J4, 1-2, 11-12, 13-14 , 17-18
JMP
9, 2 TO 3 JMP 12, 1 TO 2
JMP
10, OFF
I
have done these mods to over 12 MFJ –1270s (no
B or Cs) and it seems I never see the same circuit board. I guess there was a
lot of on going changes.
To run
U-23 with UIDIGI or tnc V1.19 you must have 32 k of
ram U-25 (43256) and JMP-12, 1-2.
Do
not use the
battery backup on the tnc.
Uidigi PROM chip (27c256) always goes
in socket U-23.
Check
to make sure U-21, pin 22 (z80/sio) goes to ground.
To talk
to a UIDIGI via computer comm port, type ‘esc
key’, ‘c’, ‘return key’.
SOME
COMMANDS:
Clock
duplist
Connect
btext
Info
restart
Mheard
retry
Reset led
Test
uinly
Quit
Sysop /
pairs up with your password / netrom password request
Do
not forget to program in ‘The New-N Paradigm’ to unclutter
needless digipeating!
19,200
BAUD TO YOUR COMPUTER
Cut
the trace at pin 1 (300b SW) and run a wire from pin 1 (SW2) to U1 (4040), pin
10. Set the baud switch #1 to on.
300 baud now becomes 19,200 baud!
Revised: 02/13/10 by KC5PIY, B. B. Stanfield, Webmaster
Copyright 2006 by Intertie, Inc. All Rights Reserved
No use of these symbols or phrases is allowed without the express written
permission of Intertie, Inc.