IBM 5251 Series Maintenance Information Manual page 103

157
(continued)
- Trace the line called out in the MAP.
All signals come from the planar; however, the display
will cause an open line to continue to pulse at a high
enough level to trigger the CE probe.
Power off.
Disconnect the display AC power connector (150).
- Power on.
Check the signal at the planar.
Note: The Brightness control must be turned up
(clockwise) all the way to make the video signal large
enough to trigger the CE probe.
Is the line pulsing?
V N
- Power off.
Disconnect the cable at the display.
Power on.
Does the line pulse now?
N
Check the cable for a grounded signal line.
Is the cable OK?
V N
- Repair or replace the cable.
- Replace the planar; set the jumpers correctly on
the new planar (103) (105).
Replace the display.
Is the line pulsing at the display?
V N
I -
Check the cable for an open.
Does the MAP call out any other line that has not
been checked?
V N
- Reconnect the display AC power connector (150).
- Make adjustments if applicable (153).
- Replace the display assembly.
- Repeat this procedure for the other line.
157
•••••
.
..
Suggested action for an intermittent problem:
• Analyze the suspected line; inspect all the connector
contacts.
• Replacement sequence:
Display assembly
Planar
Display signal/planar power cable
Maintenance Procedures 5251 MIM 1-85