IBM 5280 Manual page 234

F
3
COMMUNICATIONS MAP
NON AUTO ANSWER
PAGE 4 OF
S
018
- Power off.
- Remove the 38lS card.
- Check continuity between A-D7~06
'+Data Tip' and the lead at the
coupler.
Check continuity between A-D7D08
'+Data Ring' and the lead at the
coupler.
Is continuity good?
Y N
019
Disconnect the internal cable
from the communications MPU
card at connector A-ES-J01.
At the POI connector ON THE
INTERNAL CABLE check
continuity between POI-07
'+Data Tip' and the lead AT
THE COUPLER.
At the POI connector ON THE
INTERNAL
continuity
CABLE
between
check
POI-23
'+Data Ri~9'
and the lead AT
THE COUPLER.
Is continuity good?
Y N
H
J
K
H
J
K
MAP 3013-4
020
Disconnect the external
cable from the machine at
connector J140.
At the Pl40 connector ON THE
EXTERNAL CABLE check
continuity between P140-09
'+Data Tip' and the lead AT
THE COUPLER.
At the Pl40 connector ON THE
EXTERNAL CABLE check
continuity between P140-21
'+Data Ring' and the lead AT
THE COUPLER.
Is continuity good?
Y N
021
Defective external cable.
022
- Defective internal cable.
023
Defective communications MPU
card (A-ES)(MIM 811).
If a 'Ros Patch' cable is
connected to the card~
GO TO MAP 0600, ENTRY POINT A.
024
Use the CE meter on the RXI
scale to measure the resistance
to a ground pin. A short will
read less than 20 ohms. Measure
A-D7D06, 'Data Tip', to A-D8D08,
'Gnd' (MIM 867, probe point C).
Is the line grounded?
Y N
S S
L M
EC840874
PEC839787
MAP 3013-4