IBM 5251 Series Maintenance Information Manual page 85

141
(continued)
- Check the' -power-on reset' line at the planar.
Is the line at a Down level?
Y N
Does the line pulse Down for about 1 second
during power-on?
Y N
Inspect the interposer.
- Replace the planar; set the jumpers correctly on
the new planar (103) (105).
You have taken the wrong path.
- Go to MAP 0100 Start of Call.
- Power off.
- Remove the cable at socket B.
- Power on.
Is the line at a Down level at the planar?
Y N
Check for a ground in the cable or keyboard logic
PC board.
- Inspect the interposer.
- Replace the planar; set the jumpers correctly on the
new planar (103) (105).
141
Suggested action for an intermittent problem:
• Analyze the suspected line; inspect all the connector
contacts.
• Clean the pad PC board contacts.
• Replacement sequence:
- Logic PC board
Planar
- Keyboard cables
Maintenance Procedures 5251 MIM 1-67