IBM 5280 Manual page 210

A
J
1
3
A COMMUNICATION MAP
K
1 38LS XMIT/RECV CHECK
3
PAGE
14 OF
20
075
Defective communications MPU
card (A-E5)(MIM 811).
If a 'Ros Patch' cable is
connected to the card,
GO TO MAP 0600, ENTRY POINT A.
076
Check continuity between A-D7D05
'+Data Tip (DT)', (MIM 867,
probe point C), and the White
lead AT THE COUPLER.
Is continuity good?
Y N
077
- Disconnect the internal cable
from the communications MPU
card at connector A-E5 JOl.
- At the POl connector ON THE
INTERNAL CABLE check
continuity between POI-07
'+Data Tip (DT)', (MIM 867,
probe point E), and the White
lead AT THE COUPLER.
Is continuity good?
Y N
078
- Disconnect
cable from
the external
the machine at
connector Jl40.
- At the Pl40 connector ON THE
EXTERNAL CABLE check
continuity between P140-09
'+Data Tip (DT)', (MIM 867,
probe point F), and the
White lead AT THE COUPLER.
Is continuity good?
Y N
A A A
L "1 N
079
- Defective external cable.
A A A
L M N
OSO
MAP 3011-14
Defective internal cable.
OSl
- Defective communications MPU
card (A-E5)(MIM 811).
If a 'Ros Patch' cable is
connected to the card,
GO TO MAP 0600, ENTRY POINT A.
082
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-D7D05, 'Data Tip', to A-DSDOS,
'Gnd' (MIM 867, probe point C).
Is the line grounded?
Y N
083
- Defective 38LS line adapter
card (A-D7)(MIM 812).
084
- Remove the communications MPU
card (A-E5)(MIM 811)
Is the line grounded?
Y N
1 1
5 5
A A
P
Q
ECS40874 PEC839787
NAP 3011-14