3-12
ELECTRICAL TROUBLESHOOTING GUIDE
4. SYSTEM TEST FLOW
A
TEST
Replace power PCBA
Repair or Replace main PCBA
YES
NO
NO
Make sure the main PCBA don’t short .
power PCBA connected to AC voltage
Repair or Replace power PCBA
YES
NO
Check or replace Q4 or Q5
YES
NO
Connect to PC RS232 cable and
update the FLASH memory code.
1. Check 27MHz system clock.
2. Check system reset circuit.
3. Check FLASH R/W enable signal WR, HOLD.
4. Check RS232 SIGNALS.
5. Check FLASH Memory related circuit.
NO
YES
Check the AC
Voltage Power PCBA
(110V or 220V)
Update FLASH
successfully?
Is the DC
voltage outputs OK?
(5 V)
Is 3.3V
and 1.2V DC outputs normal
on main PCBA?
