5. 24 MHz Adjustment (MB-80 board)7. 36 MHz Lock Check (MB-80 board)
<Purpose><Purpose>
24 MHz is the reference clock to generate 36 MHz clock, and if it isThis checks whether 36 MHz is synchronized with reference clock
not adjusted correctly, checking of 36 MHz will r27 MHz for MPEG system. If it is not locked, the sounds and pic-esult in NG.
tures are not synchronous during MPEG playing or playing is sus-
ModeE-Epended.
Test pointTP022 (512fs)
ModeE-E
InstrumentOscilloscope, Frequency counterTest pointTP021 (PH-COMP)
Adjusting element CT002
Specification24576000 ?100HzInstrumentOscilloscope, Frequency counter
Specification24.0 ?0.01 kHz
Adjusting method:
1) In the O0� Syscon Diagnosis of the test mode initial menu,Checking method:
select the DVD mode.1) In the O0� Syscon Diagnosis of the test mode initial menu,
2) Confirm that the waveform at TP022 is normal.select the DVD mode.
3) Adjust CT002 to attain 24576000 ?100Hz.2) Confirm that a rectangular wave at TP021 is locked.
3) Confirm that the frequency is 24.0 ?0.01 kHz.
Figure 7-5Figure 7-7
8. 16 MHz Check (MB-80 board)
6. 36 MHz Check (MB-80 board)<Purpose>
<Purpose>16 MHz is the reference clock for audio system to play CD (includ-
36 MHz is the reference clock for audio system to play DVD, and if
it is not adjusted correctly, no sound will be generated or soundsing video CD), and if it is not adjusted correctly, no sound will be
will be distorted.generated or sounds will be distorted.
ModeE-EModeE-E
Test pointIC770 20 pin
Test pointTP020 (36 MHz)
InstrumentOscilloscope, Frequency counterInstrumentOscilloscope, Frequency counter
Specification16934400 ?75 Hz.
Specification36864000 ?150 Hz
Checking method:Checking method:
1) In the O0� Syscon Diagnosis of the test mode initial menu,1) Confirm that the waveform at IC770 @1 pin is normal.
select the DVD mode.2) Confirm that the frequency is 16934400 ?75 Hz.
2) Confirm that the waveform at TP020 is normal.
3) Confirm that the frequency is 36864000 ?150 Hz.
Figure 7-8
Figure 7-6
7-3
ACEC
