Sony D-555 - Focus Bias Adjustment Procedure

D-555/Z555 |
Focus Bias Adjustment
Conditions:
The set should be placed either horizontally.
Adjustment
Procedure:
oscilloscope
(DC range)
servo board C)
Le 2k2
(RF) O——"——O +
Vc (1/2 Vcc) O=———_© -
(See page 6.)
oscilloscope
(DC range)
O
1C502 @8) (FE) +
VC (1/2 Vec) ! =
(See page 6.)
servo board
. Put the set into service mode (see page 5).
. Connect the oscilloscope to servo board test point
TP (RF).
. Press the PPI and M4 keys to move the UPF to
the center. (Move the UPF to the music area on
the disc to enable easy visibility of the eye pat-
tern).
. Insert the disc (YEDS-18) and close the top panel.
. Press the P&B key.
It will go from focus search to focus on, and
[cuv pull-in mode state. Tracking and sled re)
OFF.
. Press the KEY-MODE button. (Tracking and sled
go ON.)
. Adjust RV503 so that the oscilloscope waveform
eye pattern is good. A good eye pattern means
that the diamond shape (©) in the center of the
waveform can be clearly distinguished.
RF Signal Reference Waveform (eye pattern)
VOLT/DIV: 200 mV
TIME/DIV: 500nS_
\ RNIN _
KKK KAALKAY. | B6de% og y
MA
A)
0.1 V
- Push the Hi (STOP) button spindle motor from
rotating and remove the disc.
. Remove the disc and connect the oscilloscope to
main board IC502 @8) (FE).
. Adjust RV503 again refering to the table followed.
more than +50 mV | Not adjust again.
+50 mV ~ +20 mV Adjust RV503 again for +50 mV
reading on oscilloscope.
+20 mV ~ —20 mV Adjust RV503 again for -20 mV
reading on oscilloscope.
11. After adjustment, release service mode (see page
5).
Adjustment Location: servo board
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