Service Aids; Tools; Light Pen Register And Control Mini-Map; Conditions After Power On - IBM 5251 Series Maintenance Information Manual

121
LIGHT PEN REGISTER AND CONTROL
MINI-MAP
• Use this mini-MAP to correct a light pen problem
when the light pen feature causes a problem on the
keyboard or display or when the cursor is unstable
immediately after power-on.
• For mini-MAP example, see Troubleshooting Aids
(212).
Conditions After Power On
• The reg 13 'bits 1, 2, 4, 5, and 6' lines are at an Up
level.
• The reg 13 'bits 0, 3, and 7' lines are at a Down
level.
• The' -LNC' line is pulsing.
• The' - LP photocell' line should be at an Up level.
Service Aids
• The display station will not be damaged if it is
powered on after the keyboard, MSR, or light pen
has been disconnected.
Tools
Connect the CE probe as follows:
• +
lead-1-G-D03
• - lead-1-G-D08
• Ground-1-B-D08
Maintenance Procedures 5251 MIM 1-33