Hitachi 42HDM12 Service Manual page 17

No signal issue (Composite, SV, YCbCr, YPbPr)
No signal
Check if the signal source
is available and been well
connected?
Check if the PCB-I/O has
been well connected to
the PCB-Main?
Take off the back cover.
Check if Wire Ass'y 31P
has been well connected to
PCB-Main?
Change the PCB-I/O
then check the signal
Yes
Yes
Yes
Yes
17
Enable source and
No
connect the signal wire
properly.
No
Connect the PCB-I/O
properly.
No
Connect Wire Ass'y 31P
properly to the
PCB-Main.
No
Change
PCB-Main board
Test
again