Hitachi P50H401 Service Manual page 121

IN DEPTH TROUBLESHOOTING OF DIGI-MAIN RELATED TO AUDIO PROBLEMS
No sound, abnormal sound
Are waveforms at
terminals of speaker
OK?
No
Cable/Air, Input 1/2/3/Front
Are waveforms at
Vias 1(R) and Vias 2(L) at the
Main-Digital board
OK? *
No
Are all analog inputs failing?
No
Input 1 or input 2 or
Input 3 failing?
No
Is Input-Front failing?
No
Is analog audio
signal from tuner
failing?
No
Is Monitor Out
audio failing?
Trouble-shooting guide for audio failure.
Yes
Check Speaker
HDMI1/2
Yes
Repair/Replace
Main-Digital board
Is there DC level (+5Vdc) in
Yes
the checked waveforms of the
mentioned Vias1(R) and Vias
Yes
Repair/Replace the
Terminal board.
Check the Input-Front terminal or the Control board or the
Yes
connector from control board to the terminal board. Check
the waveforms at TP07(L), TP08(R) which are next to the
PTC connector base in the Terminal board.
Is audio signal
Yes
failing from tuner UT01
pin no. 15 (R) or
no. 16 (L)?
Yes
Repair/Replace the
Terminal board.
120
HDMI-FRONT
Are SD
Yes No
Board and EMH
Flat connector to
Digi-Main
OK?
Waveform at
Vias 1 and Vias 2
1KHz sine wave, 1.5Vpp.
* Note: Check the location of
the Vias at the end of this flow
chart.
Yes
2(L)?
No
B
Repair/Replace the
Yes
tuner or the Terminal
No
Follow "A" instruction
in video
troubleshooting of
A
terminal board.
Cable/Air
Repair/Replace SD
board or connector.
Repair/Replace the
Terminal board.
Go to the next page...
board.