Service manual

SERVICE MANUAL LS07 chassis
23
3 White screen: the reason of the troubleshoot is the signal electrode
electrode haven’t working voltage. The TFT is always in transparent condition,
so the whole screen is in white raster.
VLCD of screen socketJ16(J17Ўў J22) in
main board is normal or not?
NO
YES
Check Q25Ўў U19Ўў FB39Ўў
FB40Ўў FB41, ect parts of an
apparatus
Check the jointing of screen socket in main
board is OK or not?
NO
YES
Patch jointing
Switch signal source,use the
oscillograph to check the signal input
or not
Check PCB copper aluminium
connect line
Check U2 outside circuit is normal or
not ,change the fault ones.
YES
NO
(4) Picture abnormalcolor abnormal short of color
Observe the picture is different in one
condition by the mode of switch signal
source
Check U20 and i t ЎЇ s
out si de ci r cui t , check
t he Q12Ўў Q14Ўў Q15 i s
nor mal or not
Check U6 and i t ЎЇ s
out si de ci r cui t i s
nor mal or not
Check the jointing of screen
socket J16Ўў J17Ўў J22 in
main board is OK or not,the
connection is OK or not
TVЎў AV condition picture
different
HDЎў VGAcondition picture
different
all appear picture different
normal
Check the output of 85thЎў
86thЎў 87th pin of U2
Check FB1Ўў FB2Ўў FB3Ўў
FB4Ўў FB5 inductance are
normal or not
Check U2 outside
circuit is normal or
not,change fault ones
normal
normal