IBM 5251 11 Maintenance Information Manual page 50

140
(continued)
- Probe cable check 8 (8-D12) at the planar.
Is the line at a Down level?
Y N
140
Check for an open through the cable and keyboard
logic PC board back to ground on the planar.
Inspect the interposer.
Replace the planar (set the jumpers correctly on the
new planar (103) (105) ).
Suggested action for an intermittent problem:
• Jumper 1-8-D02 to 1-8-012
• If the problem still occurs, replace the planar. If not,
the cable or keyboard logic PC board could be open.
Maintenance Procedures 5251 MIM 1-31