LG GC260W Service Manual page 25

C.
Non working functon buttons.
Is the voltage of IC501 Pin 99, 5V?
YES
Does LED CLOCK, LED DOT display
change when a function button is
pressed?
YES
Replace IC501.
D.
LED CLOCK, LED DOT doesn't work.
Is 5V applied to IC501 Pins 37 and
IC5F1 Pins 5, 18?
YES
Check the ( OPTION 1)
YES
Do pulse appear at IC501 Pins 65, 66
and 67.
YES
Do oscillation appear at IC5F1 Pin1.
YES
Check the foil patterns between IV5F1
and OPTION2.
YES
Replace OPTION 2
NO
NO
NO
NO
NO
OPTION 1 : D5E4 LED CLOCK
OPTION 2 : LED 501 - LED CLOCK
LED 502 - LED DOT
3-12
Check the power.
Replace the defective Switch.
(Function SW)
Check the power circuit.
Replace IC501.
Replace IC5F1.