CASIO LX-271
Service Manual

PRECAUTIONS
To prevent damage of the thermal head caused by static electricity when assembling the chassis ass'y into the unit, the following steps must be followed; 1 : Turn the power switch off. 2 : Discharge the capacitor C18(2200µF) on the PCB L271-1. CN301 3 : Connect the FPC of chassis ass'y into a connector CN301 of PCB L271-2. 4 : Assemble the chassis ass'y. 5 : Turn the power switch on.
PCB L271-2

FPC

C18

LSI1

Chassis ass'y

ADJUSTMENT
Adjustment of low battery detection circuit

PCB L271-1

Figure-4

To adjust the threshold voltage of the low battery detection circuit, the following steps must be followed; 1 : Apply 6.2V + 0.1V / -0V to the battery terminals. 2 : Ground check pads CP45 and CP46. 3 : Adjust a pot VR1 so that the voltage between CP1 and CP2 is 0V ± 10 mV.
Multi-meter PCB-L271-1

+

CP2 CP1

VR1 CP46

BATT

-

CP45

+
6.2V (+0.1 / -0 V) Power supply

BATT +

GND

Figure-5 Setting the thermal head rank Set the thermal head rank with pads RNK1 and RNK2 on the PCB L271-1 according to the following conditions when replacing the chassis ass'y or thermal head. The head rank is indicated on FPC as following figure-6. Head rank A : RNK1=ON, Head rank B : RNK1=OFF, Head rank C : RNK1=ON, Head rank D : RNK1=OFF, RNK2=OFF RNK2=OFF RNK2=ON RNK2=ON

XXXXXXB
Head rank = B
XXXXXXB

Figure-6
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Chassis ass'y