Kenwood 1050MD Service Manual page 11

4-7 Precaution on use of test mode
An erasure prevention control is not detected in the test
mode. Therefore, when the recording laser power mode
such as continuous recording mode and traverse adjust-
ment mode is entered, the contents of the existing record-
ing are erased irrespective of the control position. Be care-
ful not to enter the continuous recording mode and traverse
adjustment mode when using a disc, containing the data
that should not be erased, in the test mode.
5. Electrical adjustment
5-1 Precaution during confirmation of Laser Diode
emission
During adjustment, do not view the emission of a laser diode
from just above for confirmation. This may damage your eyes.
5-2 Precaution on handling of Optical pick-up (KMS-
260A)
The laser diode in an optical pick-up is easy to be subject to
electrostatic destruction. Therefore, solder-bridge the laser tap
on the flexible board when handling the optical pick-up.
When removing the flexible board from the connector, make a
solder bridge in advance, then remove the board. Be careful
not to remove the solder bridge before inserting the connector.
Moreover, take careful measures against electrostatic destruc-
tion. The flexible board is cut easily. Handle the flexible board
with care.
Pick-up
5-3 Precaution during adjustment
1) Perform the adjustment and confirmation marked with "O"
in the order shown in the table when the parts below are
replaced.
2) In the test mode, perform the adjustment. After adjustment
is completed, cancel the test mode.
Optical
pick-up
1. Temperature compen-
sation offset adjustment
2. Laser power adjustment
3. Traverse adjustment
4. Focus bias adjustment
5. Error rate confirmation
3) Perform the adjustment in the order described.
4) Use the following tools and measurement equipment.
• CD test disc TGYS-1
• Laser power meter
• Oscilloscope (with bandwidth of more than 40 MΩ)
(Calibrate the probe before measurement.)
• Digital voltmeter
• Thermometer
CIRCUIT DESCRIPTION
Flexible board
Laser tap
BD board
IC6 D101 IC1,IC2,IC10
X O O O
O O X O
O O X O
O O X O
O O X O
1050MD/DM-5090/DM-9090
5) Take care that VC and GND (ground) are not connected
on the oscilloscope when two or more signals are moni-
tored on the oscilloscope. (VC and GND are short-cir-
cuited in this case.)
Note : The "#" display on the screen indicates an arbitrary
figure.
5-4 Creating the recordable continuous recording
disc
This disc is used for focus bias adjustment and error rate
confirmation. How to create the recordable continuous
recording disc is described below.
1. Insert a commercial recordable disc (blank disc).
2. Turn the JOG DIAL to display "CREC MODE."
3. Press the ENTER key to display "CREC IN".
4. Turn the JOG DIAL (CW ) to display "CREC-MID".
5. After pressed the ENTER key, a display indicates
"CREC(0300)" and the recording begins.
6. Terminate the recording within five minutes.
7. Press the DELETE key to stop the recording.
8. Press the EJECT key to take out the recordable disc.
As a result, a continuously recorded disc can be created for
focus bias adjustment and error rate confirmation.
Note : Take care that no vibration is applied during continu-
ous recording.
5-5 Laser power adjustment
Connection :
Objective lens of
optical pick up
X33
ADJUSTMENT
TP2
TP1
Adjustment :
1. Put the laser power meter on the objective lens of the
optical pick-up. Connect the digital voltmeter to TP1 and
TP2.
2. Turn the JOG DIAL to display "LDPWR ADJUST".
(Laser power : For adjustment use)
3. Press the ENTER key to display "(0.9mW)$##".
4. Adjust to turn JOG DIAL so that the laser power meter
reads 0.86 - 0.94mW.
Set range 10mW of the laser power meter,then save to
press ENTER key.
5. "(7.0mW)$##" is displayed.
6. Adjust to turn the JOG DIAL so that laser power meter
reads 6.9-7.1mW, then save to press ENTER key.
("LDPWR<$##" is displayed monentarily.)
Laser
power meter
Digital
voltmeter
+
-
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