IBM PCjr Hardware Maintenance And Service page 168

1. The voltages at connector LP should be within the
ranges hsted below.
Warning: Do not short pin A1 to any other pin.
A short will damage the system board.
2. Measure the voltages now.
g lIlHiir
1 2 3
A • • •
B ••
Low Vdc High Vdc
Pin B1 to PinAI 11.5 12.5
Pin B1 to Pin A3 4.5 5.5
WERE YOU ABLE TO READ THE CORRECT
VOLTAGES?
The system board is bad. Replace it.
Repeat advanced POST and the advanced
tests to ensure that the IBM PCyr is operating
correctly.
Light Pen 3-800-3