Sony D-555 - Laser Diode Emission Check Procedure; Emission Check Overview; Laser Diode Check Procedure

D-555/Z555 |
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 objec-
tive lens in the optical pick-up block. Therefore,
when checking the laser diode emission, observe,
from more than 30cm away from the objective lens.
Laser Diode Check Procedure
The laser diode on this set will not emit unless the
top panel is closed and S901 (leaf SW type) is turned
on. The laser diode will always emit even if focus
search is not performed in service mode.
The laser diode is checked using the current value
which flows to the laser diode inside the UPF.
Procedure 1 (service mode or normal operation)
Check the laser diode emission with the eye.
1. Open upper panel.
2. $901 onas Fig. 1.
(In service mode, this operation is not neces-
sary.)
3. Pressthe PI key.
(In service mode, this operation is not neces-
sary.)
4. Observe the objective lens and confirm that
the laser diode is emitting light. At this time,
the laser diode goes on about 10 seconds due
to focus serarch. If it does not, APC circuit
or UPF is defective.
$901
Fig. 1 Turning S907 on
Procedrue 2 (service mode or normal operation)
Check by the curent with flows in the laser diode.
1. Close the top panel,
2. Remove the main board and read the current
value on the label affixed to the UPF.
(Label on UPF)
KSS-167B
JAPAN
S 123 current value
This means 49.9 mA.
The current value varies with the set.
3. Connect a VOM as shown in Fig. 2.
4. Press the PJ key.
5. Calculate the current by the VOM reading.
VOM reading (V) + 10 = current (A)
ex. VOM reading =0.49 V
0.49 + 10 = 0.049 (A) = 49 (mA)
6. Confirm that the ammeter reading is within
the range given below.
value on label*?, mA (25°C)
variation relative to temperature:
0.4 mA/°C
(Current increases when temperature rises
and decreases when it drops.)
If the value is more than the range given,
APC circuit has been defective or the laser
diode has deteriorated. If it is less, APC
circuit or UPF is defective.
— servo board —
VOM
(dc 3 V range)
Fig. 2 VOM Connection