Electrical Adjustment; Md Section - Sony HCD-MD555 Service Manual

List of Service Tools
• Oscilloscope
• Digital voltmeter
• Thermometer
• Laser power meter LPM-8001
(Part No. J-2501-046-A)
or
• MD laser power meter 8010S
(Part No. J-2501-145-A) (Note)
• BD board waveform check jig
(Part No. J-2501-149-A)
• Check disc (MD) TDYS-1
(Part No. 4-963-646-01)
• Test disc (MDW-74/AU-1)
(Part No. 8-892-341-41)
• Test CD YEDS-18
(Part No. 3-702-101-01)
• Extension cable (19-conductor, 1.25 mm) A
(Part No. J-2501-011-B)
• Relay board (19-conductor, 1.25 mm) B
(Part No. J-2501-168-A)
B
MAIN board
CN300
• Extension cable (17-conductor, 1.25 mm) C
(Part No. J-2501-167-A)
MAIN board
CN301
• Extension cable (4-conductor) D
(Part No. J-2501-165-A)
MAIN board
CN302
SECTION 6

ELECTRICAL ADJUSTMENT

A
BD board
CN101
CONNECTOR board
CN701
C
LAD MOTOR
board
CN713
D
— 43 —

MD SECTION

Precautions for Checking Laser Diode Emission
To check the emission of the laser diode during adjustments, never
view directly from the top as this may lose your eye-sight.
Precautions for Use of optical pick-up (KMS-260A)
As the laser diode in the optical pick-up is easily damaged by static
electricity, solder the laser tap of the flexible board when using it.
Before disconnecting the connector, desolder first. Before connecting
the connector, be careful not to remove the solder. Also take adequate
measures to prevent damage by static electricity. Handle the flexible
board with care as it breaks easily.
pickup
Precautions for Adjustments
1) When any of the following parts is replaced, perform the
adjustments and checks to which a circle (O) is put in the table
below, in the following order.
Optical
Pickup
1. Initial setting of
g
adjustment value
2. Saving the IOP
information (the value
g
that is indicated on the
pickup)
3. Temperature
G
compensation offset
adjustment
g
4. Laser power adjustment
g
5. Traverse adjustment
g
6. Focus bias adjustment
g
7. Error rate adjustment
8. Auto gain output level
g
adjustment
2) Perform the following adjustments in the test mode.
When the adjustments are completed, exit the test mode.
Perform the following adjustments and checks using the "Grope
S" of the test mode.
3) Perform the necessary adjustments in the order shown.
4) When observing several signals on an oscilloscope, make sure
that VC and ground are not shorted inside an oscilloscope.
(VC and ground will be short-circuited.)
5) When the above described "BD board waveform check jig" (Part
No. J-2501-149-A) is used to observe waveforms, waveforms
can be observed without soldering.
flexible board
laser tap
BD Board
IC171 D101 IC101
g G g
g G G
g g G
g G g
g G g
g G g
g G g
g G g