IBM 5280 Manual page 83

A
D
1
o
050
- Power off.
DATA ENTRY MAP
A-Al DISPLAY
PAGE 11 OF 18
Disconnect A-AI-POl (MIM 217).
Power on.
- ChecK io
Brightness Control and Contrast
Control are fully clockwise.
Probe A-Al-TPIO, '+ Video
Drive' (MIM 200, 217).
Up light: On
Down light: On
Are the lights correct?
Y N
051
- Probe A-AIB04, 'IS MHz clock'
O'1I t1 5 3 1 ) •
Up light: On
Down light: On
Are the lights correct?
Y N
052
- Probe A-CSB03,
Clock' 0-lIM 531).
Up light: On
Down light: On
'18
Are the lights correct?
Y N
1
1
2 2
A A A A
E F G H
t1Hz
A A
G H
MAP 1010-11
053
Power off.
- Set the CE meter to the RXI
scale.
A-C8B03, '18 MHz clock', and
the negative lead to ground.
Is the meter reading 30 ohms or
above?
Y N
054
- Leave the meter connected
as in the previous step.
Use the net list (MIM 531).
Remove each card in the
net, one at a time, until
the meter reads 30 ohms or
above.
- Replace
the last card
removed.
If all cards in the net
have been removed and the
meter reading is still
below 30 ohms, suspect a
ground on the Logic Board.
055
- Defective Diskette/Main MPU
car d (A- C 1) ( M I
1' 1
303).
If
a 'ROS Patch' cable is
connected to the card,
GO TO MAP 0600, ENTRY POINT A.
056
- Defective Keyboard/Display MPU
car d (A- AI) ( M 1M2 0 0 ) .
If
a 'ROS Patch' cable is
connected to the card,
GO TO MAP 0600, ENTRY POINT A.
PEC839787
MAP 1010-11