IBM PCjr - Page 387

1. Remove the top cover. Disconnect CN6 on the
driver control card. Check for 22 ohms resistance
between pin CN6-10 (male end) and pins CN6-1
through 9. Replace the print mechanism assembly if
there are any shorts or opens.
2. Power on. Check for +24 Vdc at pins CN6-1
through 9 on driver card (use groimd pin for
common lead). If any pin has +24 Vdc, replace the
control cards. If all pins read 0 Vdc, Power off and
reconnect CN6. The print head circuitry is
functional.
Graphics Printer 4-1400-55