IBM PCjr Hardware Maintenance And Service page 217

Error message "4300" appeared.
1. Ensure that the graphics printer's power cord is
connected to a functioning, properly grounded
outlet.
2. Ensure that the printer cable is connected to the
graphics printer and system unit correctly.
3. Set the graphics printer's Power switch to OFF,
then to ON.
4. Repeat the advanced test (ID "A").
DO YOU HAVE "4300" UNDER THE GRAPHICS
PRINTER SYMBOL?
The problem has been corrected. Repeat
advanced POST and the advanced tests to
ensure that the IBM PCyr is operating
correctly.
Parallel Printer Attachment 3-900-9