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3. No display
Are the voltage VD1 ~ VD4 OK ?
Are the voltage VT1 ~ VT4 OK ?
Are the voltage VREG 2 and
VREG 4 OK ?
Are the voltage V0 ~ V4 OK ?
Is the voltage VREG 3 OK ?
Check or replace the chip
capacitor C13, C14
Replace
Y
Y
Y
Y
Y
N
Y
N
N
N
Is the voltage SW OK ?
Replace
Check or replace the chip
capacitor C11, C12
Check or replace the chip
capacitor C9 or C16
Check or replace the chip
capacitor C18 or C25
Check or replace the chip
capacitor C10
N
N
N
Y
N
Is the heat seal defective ?
Is the LCD defective ?
Y
Clean and adjust pressure of contact
Clean or replace the rubber key
Resolder
Check or replace the electrolytic
capacitor C1
Clean and adjust pressure of contact
Replace
Replace the ceramic oscillator
Y
Y
N
N
N
N
Y
Y
Y
Y
N
N
N
Y
START
Does the ceramic oscillator oscillate ?
Are the chip capacitors C22, C23 defective ?
Is the battery switch contact weak?
Is the AC key contact weak?
Are there short circuit around
the pins of the LSI?
Is the battery contact weak?
Is the voltage VCC 3[V] ?
Replace the PCB ass'y
