Philips MDV434/55/77 Service Manual page 19

Remote reception is insensitive or fails.
Remote reception is
insensitive or fails.
Check if the remote
control works properly.
Check if the power supply
voltage to the remote censor
is normal are normal.
Use an oscilloscope to check if there is
output waveform from the first pin IR of the
remote censor after pressing button on the
remote control.
Check if there is IR
signal on pin 106 of U3
Correct connection
Go
Yes
Yes
Yes
No
4-9
No
Check battery
No
Check R315、C315
No
U201(PIN 3 - RC waveform)
Yes
Change U3
IR waveform
Trouble shooting chart