Samsung YP-Q1 Service Manual page 16

Yes
When power Key is on,
check key signal as 'HIGH'?
 Refer to wave pattern
image of Fig. 4-1.
Check 7WH74_IC301 the
DODC_EN is 'HIGH'.
 Refer to wave pattern
image of Fig. 4-1.
Yes
Check MAIN 12Mhz clock
Completion
Samsung Electronics
2
No
3
No
No
Defective
Check power.
Yes
L301: 1.1V(CPU Core)
L302: 3.0V(MAIN)
Yes
Yes
Check the power terminal connection
(Battery, Adapter)
Check power at the BATTERY
(single part).
Recheck after replacing the battery.
Troubleshooting
A
4
 Refer to wave pattern
No
image of Fig. 4-1.
1
No
4-3