LG TL-AT130M Service Manual page 18

ELECTRICAL TROUBLESHOOTING GUIDE
(3) When the C(Color) signal doesn't appear on the screen in PB Mode
Is 5V applied to the IC301
Pin 16, 40, 55, 58, 87?
Is the Color Rotary signal applied to
the IC301 Pin 10?
YES
Is Color Rotary "H" about
1.6V?
YES
Does the Color signal appear at
the IC301 Pin 71?
YES
Replace the IC301.
(4) When the Video signal doesn't appear on the screen in REC Mode.
Is the EE signal normal?
Is 5V applied to the IC301
Pin 16, 40, 55, 58, 87?
YES
Does PB Mode operate
normally?
YES
Does the RF signal appear at
the IC301 Pin 12?
YES
Does the REC RF signal appear at
the IC301 Pin90?
YES
Check the Drum &
Drum Connector
SECTION3 ELECTRICAL
NO
NO
NO
NO
Does the X301(4.43MHz) or
X302(3.58MHz) oscillate?
YES
Does the Color signal appear
at the IC301 Pin 61?
YES
Check the circuit of the
IC301 Pin 35, 62.
NO
Check EE Mode.
NO
Check the line of the 5.3VA
Line.(Power Circuit)
NO
Check PB Mode.
NO
Is the REC 'H' signal (about
4V)applied to the IC301 Pin 30?
YES
Check REC Luminance
Pass & Color Pass.
NO
Check the circuit of the
IC301 Pin 90, 92, 94
Check the line of the 5.3VA
Line. (Power Circuit)
Check the Color Rotary
Circuit. (IC501 pin 98)
Check the Color Rotary level.
(Check the R302, R303)
NO
Replace the X301 or the X302.
NO
Check the Color Pass.
(Check the Q304)
NO
Replace the IC301.
Check the System of REC 'H'
NO
(the IC501 Pin 30 / the D301)
YES
Replace the IC301.
YES
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