Epson 20 - Manual (Page 175)

Error codes and messages (continued)
Error code Message
Color graphics adapter and CRT
501 V-RAM ERROR
503 ATTRIBUTE ERROR
504 CHARACTER SET ERROR
505 40-COLUMN CHARACTER SET ERROR
506 COLOR GRAPHICS ERROR
507 640 x 200 GRAPHICS MODE ERROR
508 SCREEN PAGING ERROR
509 LIGHT PEN ERROR
510 COLOR VIDEO ERROR
Floppy disk drives and controller
601 FLOPPY DISK CONTROLLER ERROR
602 SEQUENTIAL SEEK ERROR
603 RANDOM SEEK ERROR
604 WRITE ERROR
605 READ ERROR
606 DISK CHANGE CHECK
REMOVE ERROR
607 DISK CHANGE CHECK
INSERT ERROR
Math coprocessor (80387)
701 NOT INSTALLED
702 COPROCESSOR INITIALIZE ERROR
703 COPROCESSOR INVALID OPERATION MASK ERROR
704 COPROCESSOR ST FIELD ERROR
705 COPROCESSOR COMPARISON ERROR
706 COPROCESSOR ZERO DIVIDE MASK ERROR
707 COPROCESSOR ADDITION ERROR
708 COPROCESSOR SUBTRACTION ERROR
709 COPROCESSOR MULTIPLICATION ERROR
710 COPROCESSOR PRECISION ERROR
Parallel port
901 ERROR PIN p
Serial port (RS-232C)
1101 control signal ALWAYS LOW
1101 control signal ALWAYS HIGH
1102 TIMEOUT ERROR
1103 VERIFY ERROR
Performing System Diagnostics C-31