IBM 5280 Manual page 235

L M
4 4
COMMUNICATIONS MAP
NON AUTO ANSWER
PAGE 5 OF
5
025
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.
026
Remove the communications MPU
card (A-ES)(MIM 811)
Is the line grounded?
Y N
027
Disconnect the internal cable
from the A-E5-JOl 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-07 'Data Tip', to
POl-23 ,'Signal Ground' (MIM
867, probe point E).
Is the line grounded?
Y N
028
Defective communications MPU
card (A-ES)(MIM 811).
If a 'Ros Patch' cable ;s
connected to the card,
GO TO MAP 0600,
ENTRY POINT A.
D N P
2
MAP 3013-5
029
- Disconnect the external
cable from the machine at
connector J140.
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 P140
connector ON THE EXTERNAL
CABLE, measure from P140-09
'Data Tip', to P140-21
,'Signal Ground' (MIM 867,
probe point F).
Is the line grounded?
Y N
030
Defective internal cable.
031
Defective external cable.
032
Defective logic board.
033
Can the constant test pattern of
hex FFFF be heard at the calling
telephone?
Y N
034
035
Telephone problem
Have the customer place a call
to the telephone company.
The test ;s complete.
Return to the MDIs, answer 'Y',
and follow the prompts.
EC840874 PEC839787
N P
MAP 3013-5