Symptoms Of Trouble And Repair; General - Epson MX-80 Technical Manual

3.4 Symptoms of Trouble and Repair
3.4.1 General
This section describes the major symptoms of trouble with the MX-80, the probable causes
of trouble when each symptom appears, the check points to locate specific defects and the
repair method to correct the defects mainly by replacing and/or adjusting defective compo-
nents.
In the troubleshooting method described for each symptom in paragraph 3.4.2, if any trouble
is discovered to be attributable to a defect in the control circuit board, further analysis of the
defective control circuit board can be made by referring to paragraph 3.4.3 (Troubleshooting
of control circuit board), to find out which one of main IC's (8049, 8155 and 8041) attached
to the IC sockets is defective. By merely replacing any defective main IC on the control cir-
cuit board, troubleshooting of the control circuit board may be completed. However, since
these IC's perform data transfer mutually, it may be necessary to employ a cut-and-try meth-
od to some extent, in troubleshooting them.
The troubleshooting methods described in this section premise the following. Should any
electrical or mechanical part of the MX-80 fail, the defective part is repairable by replace-
ment in units of components as shown in Table 3.3 or 3.4.
With respect to the M-3210 printer mechanism, components may also be supplied
individually for parts replacement by trained personnel who have sufficient knowledge of the
operating principles of the M-321 0, as well as the disassembly, assembly and adjustment
procedures of the printer mechanism. Refer to the Technical Manual of the M-321 0 Printer
Mechanism for detailed information on the operating principles, maintenance and repair of
the printer mechanism. In this manual, however, it should be noted that when troubleshoot-
ing the M-321
°
printer mechanism, only its major components listed in Table 3.4 are subject
to replacement.
Table 3.3 Replaceable Circuit Components
Name of component Part number
Filter circuit board unit
G490302000 (115V)
G490301 001 (220/240V)
Power transformer set G490307000 (115V)
G490306000 (220/240V)
Driver circuit board G490202000
Control cirCUit board
G490201001
(including 8049. 8155 and 8041)
8049 (CPU) Al01680492
8155 (RAM and I/O) Al01681551
8041 (slave CPU) Al01680412
Control panel G490203000
Table 3.4 Replaceable Mechanical Components
Name of component
Part number
Home position sensor assy
F303030000
PTS sensor board assy
F303029000
Timing belt motor assy
F303027000
Paper feeding motor assy
F303031 000
PE board assy F303009000
Print head unit F401100000
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