Repair Procedure 12; Major System Controller Error Codes - NCR PC4i Service Manual

LEVEL 1 DIAGNOSTICS ERROR RETURNS
((PIO,
(U47) and data latch U69 (U56) to the printer
port. Refer to Detail Code 01.
DETAIL CODE 04
Susp e c t
interrupt controller ((8259, U25 (U132)). Check
the operation of -ACK from the printer port (J2
pin 5). Check U23 (U12*) (tri-state buffer for
interrupt 7) for proper operation.
PRINTER ERROR TEST
Format of code:
PERIPH:03:ww
Where,
Detail code:
DO = 1 : Printer time out
D3 = 1 : I/O error
D4 = 1 : Printer select
D5 = 1 : Out of paper
D6 = 0 : Ack (internal)
D7 = 0 : Printer busy

Repair Procedure 12

Refer to previous Repair Procedure 11. Check the
installation
connection or printer switch settings.

MAJOR SYSTEM CONTROLLER ERROR CODES

Diagnostic Error Codes 01, 03» 04, 05, 06, 07 are
associated with failures on the main processor board.
To analyze the error condition requires the use of an
oscilloscope. However, some of the components are
installed in sockets and can be removed. Replacement
of defective socketted components may alleviate the
error condition.
5-46
U35 (U46))
Interrupt
ww = Detail code
of the printer;
through line
#7 not o p e r a t i o n a l
Date Time
suspect
driver U61
at
bad cable