Atari XMM801, Field Service Manual, Page: 27 / 49

REF.7-15 Check pin status on signal connector CON 9, 10
(Pin Assignment)
Pin 3. DATA INPUT (to Host Computer)
4. GND
5. DATA OUT (from Host Computer)
6. GND
7. COMMAND (from Host Computer)
Low when Host Computer is sending a
command frame to the printer
10. READY (from Host Computer)
High when Host Computer is ready.
Pin 1, 2, 8, 9, 11, 12, 13 not used by printer
-All 13 pins shall be daisy chained from one SIO
connector to the other, i.e. connect pin 1 to pin 1,
pin 2 to pin 2 and so on.
-For reference DATA IN, DATA OUT and COMMAND should
Show the pulse wave, refer to FIG.l,m while printing.
REF.7-16 Check Print Signal on CPU (7811).
-While printing, Pin 9 thru 16 should show pulse wave,
refer to FIG. n-similar wave.
Pulse width is typically 600
µ
sec.
REF.7-17 Check Print signals on the driver.
-Connect plus lead of scope to Anode side of Diode ZD4
then check following points by minus leadoff scope:
Pin 7, 2, 15, 10 (IC3) 7, 2, 15, 10 (IC4) should
show pulse wave refer to FIG.o-similar wave.
CAUTION: For this check, the scope should be floating
from GND.
REF.7-18 Check paper feed signals.
-Some 2pins in Pin 4 thru 7 of IC5 should show High
level, other 2 pins should show Low level when not
feeding paper, and in paper feeding should show pulse,
refer to FIG.q-similar wave.
REF.7-19 Check circuits for Paper Feed Motor, in feeding.
Check pin 10 thru 13 of IC5 while paper feeding and
refer to FIG.r-similar wave.
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