TDP-643R PLUS BAR CODE PRINTER
SERVICE MANUAL
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5.5 Diagnosis Operation Procedure
When the power is turned on without any button pressed, self diagnosis is
performed automatically to test the available memory. If any error occurs during
this period, the ERR light will flash.
Do the self test and inspect the test pattern to check if the thermal head is
available.
5.6 Testing Sensor
5.6.1 Checking Gap Sensor
Do gap calibration first by holding the Pause button and activating the printer
power at the same time. If the calibration result is OK, go on and check the gap
sensor. Switch the multimeter to the DC gear. Connect the black wire to DC GND,
and the red wire to PIN2 of JP2. Load label on the printer.
1. When gap (backing paper only) is detected between TX and RX of the gap
sensor, the measured voltage should be 0 Vdc.
2. When gap (backing paper only) is not detected between TX and RX of the
gap sensor, the measured voltage should be 5 Vdc.
The gap sensor is normal if the checking complies with the two cases above. Or
else, the gap sensor is out of order.
5.6.2 Checking Peel Off Sensor
Switch the multimeter to the DC gear. Connect the black wire to DC GND, and the
red wire to PIN2 of JP1.
1. When label is detected by the peel off sensor, the measured voltage should
be 0 Vdc.
2. When label is not detected by the peel off sensor, the measured voltage
should be 5 Vdc.
The peel off sensor is normal if the checking complies with the two cases above.
Or else, the peel off sensor is out of order.
