CASIO ZX-805A
Instrukcja Serwisowa

10. TROUBLESHOOTING
1. Intermittent display
START Y Is the Heat seal defective ? N Y Is the battery contact weak ? N Are there short circuit around the pins Y of the LSI (HC3009-01-F1) ? N Is the soldering weak ? Y N Replace the PCB ass'y Replace Clean and adjust pressure of contact Resolder Resolder

2. Erratic display
START Is the Heat seal defective ? N Is the LCD defective ? Y Y Replace Replace Check or replace the chip capacitors C4 ~ C8 Resolder

N N Are the voltage V0 ~ V4 OK ? Y Are there short circuit around the pins of the LSI (HC3009-01-F1) or between the 2 pins of Y the crystal oscillator (·1) ? N Are there short circuit around the pins of the RAM and ROM ? N Replace the PCB ass'y

Y

Resolder

� 20 �