Epson LQ 1050 - B/W Dot-matrix Printer - PDOS for RAM and CPU Check

REV.-A
5.2.6 PDOS for RAM and CPU Check
If you want to run only the RAM check or CPU check, you do not need the host computer.
Install the diagnostics ROM in the printer at location
IC4A.
LOCATION
NOTE: Check does not require connection to a host
FX-850/1050
IC4A
PRINTER DIAGNOSTICS
computer.
ROM
Figure 5-7. RAM and CPU Check
(1) Turn the power on.
(2) Check to see if the ONLINE LED light is on or off.
(3) Check to see if any
LEDs are blinking.
POWER ON
J
(NO)
POWER\ READY/PO/ONLINE LEDs ON -~
I (YES)
J
(NO)
ALL LEDS TURNS OFF
+
I (YES)
+
(NO)
ONLINE LED ON
●
I
(YES) FINISH
IC7C INITIALIZE
(NO)
PAPER OUT LED ON
+
1
(YES) FINISH IC3A INITIALIZE
(NO)
READY LED ON
●
I (YES) FINISH IC4B INITIALIZE
J
(YES)
ONLINE LED BLINKS
●
1
(NO)
(YES)
PAPER OUT LED BLINKS
●
I
(NO)
(YES)
READY LED BRINKS
+
I
(NO)
(NO)
BUZZER BEEPS
●
I
(YES)
READ DIP SWITCHES
CHECK
+5V LINE
CPU DOES NOT WORK.
REPLACE IC7A.
REPLACE
IC3A.
REPLACE
IC4B.
REPLACE IC5A (RAM ERROR)
REPLACE IC6A (RAM ERROR)
REPLACE
IC4B(RAM ERROR)
REPLACE
IC7A
(Perform Function. IF DIP SW1 =OOH then stop)
5-7