Service manual

Buffalo BU1715
40
4. U401-Data Output
8.2.2 Key Board
OSD is unstable or not working
Is Key Pad Board connecting normally?
Connect Key Pad Board
Is Button Switch normally?
Replace Button Switch
Y
N
N
Is Key Pad Board normally?
Replace Key Pad Board
Y
N
Y
Check Main Board
NG
Measured X401 waveform is
normal?
Check TSU16AK (U401)
Signal output (PIN102-103,
106-113,118-125,128,1)
Is the waveform ok?
Replace X401
Check HS/VS input signal are
normal?
OK
Replace U401
OK
OK
Check relative component
NG
NG