Chart Of Troubleshooting; Baseband; Power On - Samsung SGH-U100 Service Manual

3. Flow Chart of Troubleshooting

3-1 BASEBAND

3-1-1. Power ON

'Power On' does not work
Yes
Check the current
consumption more
than 100mA
Yes
Check the VBAT
more than 3.3V
Yes
Check the
VLDO7_1.8V
of U300 is more than
1.8V
Yes
Check U305
pin 6, 8 = 1.5V
pin 2 = 1.8V
pin 9 = 1.6V
Yes
Check VRF of
U300=2.8V
Yes
Check C136
Freq = 13MHz
Vp-p > 0.8V
Yes
Check the initial operation
Yes
END
3-1
No
Download again
No
Charge the Battery
①
No
Check U300 and C319
②
No
Check U305
③
Check U300
No
and C320
④
No
Check the clock C136