Servicing Notes - Sony D-NF400 Service Manual

D-NF400/NF401
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NOTES ON HANDLING THE OPTICAL PICK-UP
BLOCK OR BASE UNIT
The laser diode in the optical pick-up block may suffer electro-
static breakdown because of the potential difference generated by
the charged electrostatic load, etc. on clothing and the human body.
During repair, pay attention to electrostatic breakdown and also
use the procedure in the printed matter which is included in the
repair parts.
The flexible board is easily damaged and should be handled with
care.
NOTES ON LASER DIODE EMISSION CHECK
The laser beam on this model is concentrated so as to be focused
on the disc reflective surface by the objective lens in the optical
pick-up block. Therefore, when checking the laser diode emis-
sion, observe from more than 30 cm away from the objective lens.
• In performing the repair with the power supplied to the set, re-
moving the MAIN board causes the set to be disabled.
In such a case, make a solder bridge to short SL825 (OPEN/
CLOSE DETECT) on the MAIN board in advance.
– MAIN Board (Conductor Side) –
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SECTION 1

SERVICING NOTES

SL825
(OPEN)
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BEFORE REPLACING THE OPTICAL PICK-UP BLOCK
Please be sure to check thoroughly the parameters as par the "Op-
tical Pick-Up Block Checking Procedures" (Part No.: 9-960-027-
11) issued separately before replacing the optical pick-up block.
Note and specifications required to check are given below.
• FOK output: IC601 yg pin
When checking FOK, remove the lead wire to disc motor.
• RF signal P-to-P value: 0.45 to 0.65 Vp-p
LASER DIODE AND FOCUS SEARCH OPERATION
CHECK
During normal operation of the equipment, emission of the laser
diode is prohibited unless the upper lid is closed while turning ON
the S820. (push switch type)
The following checking method for the laser diode is operable.
• Method:
Emission of the laser diode is visually checked.
1. Open the upper lid.
2. With a disc not set, turn on the S820 with a screwdriver having
a thin tip as shown in Fig.1.
3. Push the N X button.
4. Observing the objective lens, check that the laser diode emits
light.
When the laser diode does not emit light, automatic power
control circuit or optical pickup is faulty.
In this operation, the objective lens will move up and down 4
times along with inward motion for the focus search.
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S820
Fig. 1 Method to push the S804
co
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0 5 8 2 9 9 4 2 8
detection lever
detection lever
MAIN board
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