Sharp LL-153A Service Manual page 31

15" LCD Color Monitor
4. U4-DATA OUTPUT
Measured DCLK(pin 65,66 from U401)
DVS, DHS (pin 63,64 from U401 )
Is the waveform ok?
DCLK around 48 MHZ , DVS=60.09Hz , DHS around 80
KHz ?(refer to input signal=640x480@60 Hz 31k, and
LED is Green)
Check TSUM13AK(U401)
Signal output (PIN105-114, 118-127)
Is the waveform ok ?
8.2.2 Keypad Board
OSD is unstable or not working
Is Key Pad Board connecting normally?
Is Button Switch normally?
Is Key Pad Board normally?
OK
OK
OK
Y
Y
Y
Check main board
NG , no transition
Replace TSUM13AK (U401) or
replace Main board.
If Main Board being replace, please
do the DDC – content reprogrammed
N
Connect Key Pad Board
N
Replace Button Switch
N
Replace Key Pad Board
31
Sharp LL-153A