Adjustment Of System Control; 27 Mhz Free Run; 22 Mhz Adjustment; 33 Mhz Check - Sony dvp-s3000 Service Manual

7-3. Adjustment of System Control

1. 27MHz Free Run (MB-80 board)
<Purpose>
27MHz is the reference clock for the MPEG system, and if it is not
adjusted correctly, checking of 22 MHz and 33 MHz lock in the
following steps will result in NG.
Mode E-E
Test point TP018 (27MHz FREE RUN)
Instrument Oscilloscope, Frequency counter
Adjusting element RV001
Specification 27000000 ±100Hz
Adjusting method:
1) Connect TP025 (XULK) to the GND.
2) Confirm that the waveform at TP018 is normal.
3) Adjust RV001 to attain 27000000 ± 100 Hz.
4) After adjustment, disconnect TP025 from GND.
Figure 7-1
2. 22MHz Adjustment (MB-80 board)
<Purpose>
22MHz is the reference clock to generate 33 MHz clock, and if it is
not adjusted correctly, checking of 33 MHz will result in NG.
Mode E-E
Test point TP022 (512fs)
Instrument Oscilloscope, Frequency counter
Adjusting element CT001
Specification 22579200 ±100Hz
Adjusting method:
1) In the "0" Syscon Diagnosis of the test mode initial menu,
select the CD mode.
2) Confirm that the waveform at TP022 is normal.
3) Adjust CT001 to attain 22579200 ±100Hz.
Figure 7-2
3. 33 MHz Check (MB-80 board)
<Purpose>
33 MHz is the reference clock for audio system to play CD (includ-
ing video CD), and if it is not adjusted correctly, no sound will be
generated or sounds will be distorted.
Mode E-E
Test point TP019 (33 MHz)
Instrument Oscilloscope, Frequency counter
Specification 33868800 ±150Hz
Checking method:
1) In the "0" Syscon Diagnosis of the test mode initial menu,
select the CD mode.
2) Confirm that the waveform at TP019 is normal.
3) Confirm that the frequency is 33868800 ±150Hz.
4. 33 MHz Lock Check (MB-80 board)
<Purpose>
This checks whether 33 MHz is synchronized with reference clock
27MHz for MPEG system. If it is not locked, the sounds and pic-
tures are not synchronous during MPEG playing or playing is sus-
pended.
Mode E-E
Test point TP021 (PH-COMP)
Instrument Oscilloscope, Frequency counter
Specification 21.6 ±0.01kHz
Checking method:
1) In the "0" Syscon Diagnosis of the test mode initial menu,
select the CD mode.
2) Confirm that a rectangular wave at TP021 is locked.
3) Confirm that the frequency is 21.6 ±0.01kHz.
7-2
Figure 7-3
Figure 7-4