Read LG 42LH90QD (CHASSIS:LT91C) Service Manual online
Check MAIN B’D
JK406 Pin #1 5V ?
NO
Check MAIN B’D
R848 12V ?
Check that the USB Memory & HDD are supported by Spec
(Refer to User Manual’s USB cautions)
YES
Check MAIN B’D
R826 5V ?
Replace MAIN B’D IC808
YES
NO
Replace POWER B’D
YES
YES
Replace MAIN B’D IC 100
Check MAIN B’D
JK406 OK ?
YES
NO
Replace MAIN B’D JK406
Making
Revision
2009. 2 . 1
23/25
LCD TV
Symptom
USB No Connect Problem
36
Click on the first or last page to see other 42LH90QD (CHASSIS:LT91C) service manuals if exist.