LG TL-AT130M - Manual (Page 17)

(2) When the Y(Luminance)signal doesn’t appear on the screen in PB Mode.
3-7
Clean the Drum.
NO
NO
Is the V.H.S/W "H" about
3.4V to the IC301 Pin11 ?
Check the path of the Y(Luminance)
RF signal.(Check the Q301)
Check the path of the Y(Luminance)
RF signal.(Check Q302, Q303)
Is 5V applied to the IC301
Pin 16, 40, 55, 58, 87?
Is the I 2 C Bus signal applied
to the IC301 Pin 23, 24?
YES
Does the normal RF signal
appear at the IC301 Pin74?
YES
Check the System Circuit. (Refer to
‘SYSTEM I 2 C BUS Trouble Shooting’)
YES
YES
Replace the IC301.
Replace the IC301.
Does the Y(Luminance) RF signal
appear at the IC301 Pin 17?
YES
Is the Y(Luminance) Video waveform
showed up at the IC301 Pin 41?
YES
YES
Check the System Circuit.
(IC501 Pin 23)
NO
NO
NO
NO
Is V.H.S/W "H" about 3.4V at the
IC301 Pin 11?
YES
Check the V.H.S/W level.
(Check R304, R305)
NO
NO
Check the line of the 5.3VA
Line. (Power Circuit)
SECTION3 ELECTRICAL
ELECTRICAL TROUBLESHOOTING GUIDE