IBM 5280 Manual page 227

A
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A
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A COMt'lUN I CAT IONS MAP
N
1 CBS COUPLER
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PAGE 11
OF
13
084
-
Disconnect the external
cable from the machine at
connector J140.
- At the P140
c~~~ect~~
ON
T~E
EXTERNAL CABLE check
continuity between P140-20
'+Data Modem Ready' (MIM
867, probe point
F)
and the
Yellow lead AT THE COUPLER.
Is continuity good?
Y N
085
- Defective external cable.
086
Defective internal cable.
087
Defective c~mmun;cations MPU
card(A-ES)(MIM 811).
If a 'Ros Patch' cable ;s
connected to the card,
GO TO MAP 0600, ENTRY POINT A.
088
- Use the CE meter on the RXl
scale to measure the resistance
to a ground pin. A short will
read less than 20 ohms. Measure
A-D8D02, 'Data Modem Ready', to
A-D8D08, 'Gnd' (MIM 867~ probe
point C).
Is the line grounded?
Y N
A
P
089
Defective 38LS line adapter
card (A-D7)(MIM 812).
A
P
090
MAP 3012-11
- Remove the communications MPU
card (A-ES)(MIM 811)
I~ th~ lin~ grounded?
Y N
091
Disconnect the internal cable
from the A-ES-JOI connector.
Use the CE meter on the RXI
scale to measure the
resistance to a ground pin. A
short will read less than 20
ohms. At the POI connector ON
THE INTERNAL CABLE~ measure
from POI-lS 'Data Modem
Ready', to POl-23 ,'Signal
G r
0
un d ' ( M
Hl
867, pro b e poi n t
E) •
Is the line grounded?
Y N
1 I
2 2
A A
Q
R
092
- Defective communications MPU
card (A-ES)(MIM 811).
- If a 'Ros Patch' cable is
connected to the card,
GO TO t'lAP 0600,
ENTRY POINT A.
EC840874 PEC839787
MAP 3012-11