3-13
ELECTRICAL TROUBLESHOOTING GUIDE
4. SYSTEM TEST FLOW
A
TEST
Replace power PCBA or AC transformer.
YES
NO
Switch on the power PCBA
Check DC output from SMPS
(5 VA and 12 VA)
YES
NO
Make sure the main PCBA don't
short on VCCs and switch it on.
YES
Check 3.3V and 1.8V line
on Main PCBA?
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 PRD,
RWR.
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 supply output OK?
(3.3VA,5.3VA,12V)
Is 3.3V
and 1.8V DC output normally
on Main PCBA?
jomi