Hex Diagnosis - Epson FX-80 User Manual

1. A short circuit between the collector and the emitter of a head tran-
sistor along with a shorted dot driver winding produces:
PI, PI, PI . . . PI, PI, PI
on power-up or self-test, and
PI, PI, PI, PI
when on-line and printing.
2. Detection of high voltage produces:
PI, PI, PI, PEE
3. Errors detected by slave CPU (restricted printhead motion or PTS
sensor failure) produce:
PI, PI, PI . . . PI, PI, PI
4. The paper running out produces:
PI, PI, PI, PI (repeated five times)
Note: Except for paper-out sensing, the beeper will sound regardless
of switch setting.

Hex Diagnosis

Some computer systems change one or more codes when sending
them from BASIC to the printer. The FX's ability to dump in hexadeci-
mal lets you determine which codes are creating problems for your
system.
The hex dump facility prints each code that is being received by the
FX onto the paper as a string of hexadecimal values. You turn the hex
dump on by holding down the FF button while you turn the printer
on.
A hex printout of a program shows you exactly what the printer is
receiving, regardless of what the computer is sending. The following
program lets you check to see what codes, if any, make problems for
your computer system.
10 FOR X=0 TO 255
20 LPRINT CHR$(X);
30
NEXT X
Put the printer in hex dump status and then RUN the program.
If your system passes the codes directly to the printer without
changing them, your output looks like Figure F-1 (take your printer
off-line to make it print the final line).
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