NCR 7156, Руководство по обслуживанию

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7156 Service Guide Chapter 4: Troubleshooting
September 1998 53
Electronic Problems
Problem Possible Causes What To Do
Power Voltage too
Low/High
Improper connections in
printer. Check that connections in the printer are proper. See the
section in chapter 8 that applies to this unit’s PC board.
AC supply voltage is out
of range. Measure the voltage with an AC volt meter and check it
against the power supply label. The voltage range should be
24V
±
5%.
Problem Possible Causes What To Do
Printer Beeps Twice at
Power On (RS-232C
Models)
If printer beeps twice
during level 0 diagnostics,
it indicates that default
values have been loaded
into the EEROM. Take no action. See “Level 0 Diagnostics” for more
information.
If the printer beeps twice
at every power on, the
EEROM has failed. Replace the PC board. See “Removing the PC Board” in
chapter 9 and “Replacing the PC Board” in chapter 14.
Problem Possible Causes What To Do
LED Does Not Come On
Forms improperly
inserted. Remove obstructions in the paper path which may prevent
inserting forms properly.
Both sensors have to be covered for the LED to come on.
One of two sensors failed. Replace the sensor.
Failed LED. Replace the LED/sensor assembly. See chapter 10.
Problem Possible Causes What To Do
MICR Not Operating
Properly
MICR not installed. Make sure MICR is installed on the printer. Run the print
test to see if MICR is installed. See “Print Test” in chapter 3.
MICR improperly
connected. Run the diagnostic test to verify the MICR characters and
print the Hex values. See “Verifying Read of MICR
Characters” in chapter 3.
MICR does not read or
misreads checks. See the
note below. Readjust the MICR check reader. See the section in chapter 3
that applies to this unit.
MICR cables improperly
routed, which interferes
with “OK” adjustment. Reroute the MICR cables correctly. See chapter 14.
MICR read head does not
come up. Check the MICR solenoid connections to the PC board. See
chapter 14.
Foam pad missing or
displaced on carriage
assembly. Replace the foam pad on the carriage assembly. See
“Disassembling the Carriage Assembly” in chapter 12.
Check that the MICR read head assembly is mechanically
free.