Samsung SCH 620, Service Manual

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SAMSUNG Proprietary-Contents may change without notice
6-2
Troubleshooting
6-1-2 Abnormal Initial Operation (3.0V voltage source)
TCXO CLK
applied to U406 pin 35?
Check TCXO output,
R460 and C467.
Replace if required.
Check U304 and its neighboring
circuit. Replace if required.
Check U202, pin 2 Replace if required.
Check ‘H’ level input U304 pin 38.
Check the LED and its neighboring
circuit. Replace if required.
Check the LCD pins and its
neighboring circuit.
Replace if required.
TCXO CLK signal output
from U304 pin 37?
LCD-CS signal output
from U104 pin 10A?
CHIPX8 CLK signal output
from U304 pin 38?
LED ON?
Normal initial
display on LCD?
END
Yes
Yes
No
No
Yes
No
Yes
No
Yes
Yes
No
No
Press button
END/