IBM 5280 Manual page 86

A
Q
1
3
DATA ENTRY f'lAP
A-AI DISPLAY
PAGE 14 OF 18
074
Power off.
Disconnect A-AI-POI
217).
<MIM 200~
- Remove the +5 Vdc lead from the
Brightness Control terminal
3
<Mlfv1 217).
Measure the resistance from
A-Al-POl-14 to frame ground.
The meter should change from
approximately 0 to 100 ohms as
the Brightness Control is
turned from
maximum
maximum counterclockwise
clockwise.
to
Is the meter reading correct?
Y N
075
076
Use MIM 217 to trace the
'Brightness Control' line for
opens or grounds.
- OR
Defective Brightness Control
(MIN 077~ 217).
- Power on.
- Measure the voltage from the +5
Vdc lead, removed from terminal
3
of the Brightness Control, to
frame ground.
Is +4.5 to +5.5 Vdc present?
Y N
A A
A A A
P R S
1
MAP 1010-14
3
077
- Power off.
Remove the +5 Vdc lead from
the Contrast Control
terminal 3 (MIM 217).
Power on.
Measure the vOltage from
the +5 Vdc lead~ removed
from terminal 3 of the
Contrast Control~ to frame
ground.
Is +4.5 to +5.5 Vdc present?
Y N
078
GO TO MAP 8000,
ENTRY POINT A.
079
I
080
Repair the open wire
between Contrast Control
terminal
3
and Brightness
Control terminal
3
(MIM
217).
Defective Keyboard/Display
MPU card (A-AI) (MIM 2,00).
If a 'ROS Patch' cable is
connected to the card,
GO TO MAP 0600, ENTRY POINT A.
OSI
Use MIM 217 to trace the '+
Video Drive' line for opens or
grounds.
- - - - OR - - - - -
Defective Keyboard/Display MPU
card (A-AI) (MIM 200).
If a 'ROS Patch' cable ;s
connected to the card,
GO TO MAP 0600, ENTRY POINT A.
ECS40874 PECS39787
R S MAP 1010-14