Adjustments; Md Section - Sony ZS-M50 Service Manual

MD SECTION

5-1. CAUTION WHEN CHECKING LASER DIODE
EMISSION
Never look from directly above when checking the laser diode emis-
sion during adjustment as failure to do so may result in loss of eye-
sight.
5-2. CAUTIONS WHEN HANDLING THE OPTICAL
PICK-UP (KMS-260A)
The laser diode within the optical pick-up is extremely vulnerable
to static electricity. When handling, bridge the laser tap of the flex-
ible board on the optical pick-up with solder.
When removing the connector, first bridge the laser tap with solder.
Furthermore, do not remove the soldered bridge before reconnect-
ing. In addition, take sufficient measures when working to prevent
electrostatic damage. Take caution when handling the flexible board
since it is easily torn.
Pick-up
5-3. CAUTIONS DURING ADJUSTMENT
1) After replacing the following parts, make adjustments and checks
for the table items where indicated with a O in the order given.
Optical
pickup
1. Temperature compen-
sation offset adjustment
2. Laser power adjustment O
3. Traverse adjustment O
4. Focus bias adjustment O
5. Error rate check O
2) Perform adjustments in the test mode.
Exit the test mode when completed with adjustment.
2) Perform adjustments in the order given.
3) Use the following jig and measuring equipment:
• Check disk (MD) TDYS-I (Part no : 4-963-646-01)
• Laser power meter LPM-8001 (Part no : J-2501-046-A)
• Oscilloscope (perform measurement after calibrating the
probe)
• Digital voltmeter
• Thermometer
• BD board waveform checking jig (part no : J-2501-124-A)
5) When looking at multiple signals using oscilloscope, etc., make
sure VC and GND are not connected within the oscilloscope.
Failure to do so will short circuit VC and GND.
6) Using the special jig enables checking of the waveform without
soldering (see page 4 of Service Notes).

ADJUSTMENTS

Flexible board
Laser tap
BD board
IC171 D101 IC101,IC121,IC192
O
X O O
O
O X
O
O X
O
O X
O X O
SECTION 5
5-4. CREATING A CONTINUOUS RECORDING
DISK
• This disk is used during focus bias adjustment and error rate
check. The procedure for creating a continuous recording disk
is as follows.
1. Insert a disk (any commercially available blank disk).
2. Turn the AMS dial until "CREC MODE" is displayed.
3. Press the YES/ENTER button to display "CREC MID".
"CREC(0300)" will be displayed for an instant and recording
will begin.
4. Complete recording within 5 minutes.
5. Press the NO/CANCEL button to stop recording.
6. Press the MD EJECT button to remove the disk.
A continuously recorded disk can be created by following the pro-
cedure above for focus bias adjustment and error rate check.
Take caution as to not apply vibration to the unit during con-
Note:
tinuous recording.
5-5. TEMPERATURE COMPENSATION OFFSET
ADJUSTMENT
The temperature data at the time is saved in the non-volatile storage
memory as the standard data of 25°C.
Notes:
1. Do not make this adjustment under normal conditions.
2. Perform this adjustment in an environment with ambient tem-
perature between 22 to 28°C. Furthermore, make the adjust-
ment immediately after turning on the power when the internal
temperature and ambient temperature are between 22 to 28°C.
3. After D101 replacement, perform the adjustment after the part
has ample time to adjust to the ambient temperature.
Procedure:
1. Turn the AMS dial until " TEMP ADJUST " is displayed.
2. Press the YES/ENTER button and select the TEMP ADJUST
mode.
3. " TEMP= " and the current temperature data will be displayed.
4. To save the data: press the YES/ENTER button
To not save the data: press the NO/CANCEL button
5. After pressing the YES/ENTER button, " TEMP=
will be displayed momentarily and the display will then return
to " TEMP ADJUST ".
The display will immediately return to " TEMP ADJUST " when
pressing the NO/CANCEL button.
Specified values:
The value of TEMP=
FF, 00-0F, 10-1F or 20-2F.
– 21 –
must be within the range of E0-EF, F0-
SAVE "