Electrical Troubleshooting Guide - LG RH1777 Service Manual

ELECTRICAL TROUBLESHOOTING GUIDE

Reset or Power Check.
Check it after connecting the power cable
only on interface cable for NO Reset or
Power ON.
Are the pin 44 of
LPB271+5V, pin41 of LPB271+12V
respectively after the power cable
connecting?
YES
Does the pin #1
(Reset) of LIC271 change 0V to 3.3V
at the power supply initial input
mode?
YES
Are the LX201 oscillating?
YES
<Power>
Is the pin 5 of LIC401 3.3V?
YES
<Reference>
1.65V(VREF) : Check pin113 of LIC121?
2.2V(HDVREF): Check pin78 of LIC121
YES
OK
NO
Check the power(5V/12V) short.
Repair the SMPS Block
NO
Check the LIC401(3.3V regulator IC).
Check the LIC201, LIC121.
NO
Check the LX201(16.9MHz).
Check the LIC201.
NO
Check the LIC401.
NO
Check the LIC121.
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