No LED
Is Vcc (DVCC_3.3V)
supplied to IC103?
Check or replace IC505
YES
YES
NO
Is LED_5V & F_LED_12V is normal?
Check or replace IC207, Q210 & Q209.
YES
NO
Check or replace IC931.
No VFD
YES
VFD_12V is normal?
DVCC_5V & 3.3V is normal?
VFD_CLK, STB, DO is normal?
Check or replace Q209, Q210.
Check or replace Q204 & Q205, IC505.
Check or replace R808, R811, R814.
YES
YES
YES
NO
NO
NO
Check or replace VFD.
3-24
ELECTRICAL TROUBLESHOOTING GUIDE
jomi