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5.6 TROUBLESHOOTING
5.6.1 Basic Troubleshooting Procedure
This procedure exercises everything in the printer except the interface to the host system. If any step is not
successfully executed, refer to the corresponding troubleshooting section.
1. Turn on printer power.
A) If nothing appears on the display, see 5.6.2.
B) If <
> BAD is displayed, replace the indicated component on the main PCB or the
complete main PCB.
C) If CARRIAGE FAULT is displayed, see 5.6.6.
2. Press 12345678 and then CLEAR.
Each number should appear in the display and then all should
disappear. If this does not occur or if diagnostics don't begin to execute in the next step, see 5.6.3.
3. Execute 90 FUNCT diagnostics (see 3.7) and exercise the three sensors. If any sensor does not operate,
see 5.6.4.
4. Execute Local Printing (see 3.9) and use an 8 1/2" x 11" document.
A) If a document will not load into the printer, see 5.6.5.
B) If the carriage will not move across the document, see 5.6.6.
C) If no printing occurs, see 5.6.7.
D) If print quality is not acceptable, see 5.6.8.
E) For other possible problems, see 5.6.9. through 5.6.12
5.6.2 No Display
If nothing appears on the display on power up, check that:
1. the power switch on rear of printer is ON.
2. the input power cord is plugged into both printer and supply outlet.
3. the contrast knob below the display is set for good display contrast.
4. the fuse in the rear panel fuse holder is good.
5. input power is present on the input power cord.
6. the keypad/display cable is attached to main PCB at DP6 J7 or DP7 J8.
7. 48 VAC is present between J1 pins 1 and 3. If not, check transformer wiring (see 2.2).
8. At least 4.3 and less than 4.7 Volts is present across R14(DP6) or R61(DP7). If not, problem is in switching
power supply or power OK circuitry.
9. Replace either the main PCB or the display module.
5.6.3 Defective Keypad
If keypad depressions are not sensed proceed as follows:
1. If a single key fails but all others are OK, just that key may be replaced after the keypad is
removed (see 5.5.4).
2. If a row or column of keys all fail, a key may be permanently depressed or the problem is in the cable
between the main PCB and the keypad or on the main PCB.