Vco Adjustment (Pk-52 Board); Black Limit Adjustment (Pk-52 Board) - Sony MVC-FD85 Service Manual

2. VCO Adjustment (PK-52 board)

Set the VCO free-run frequency. If deviated, the LCD screen will
be blurred.
Mode PLAY
Signal Arbitrary
Measurement Point CH1:
Video terminal of AUDIO/VIDEO
OUT jack
CH2:
Pin 7 of CN803 of FC-72 board
(HSY)
Measuring Instrument Oscilloscope
Adjustment Page D
Adjustment Address D7 (NTSC)
DD (PAL)
Specified Value LCD TYPE SA:
t = 2.05 ± 0.10 µsec (NTSC)
t = 3.55 ± 0.10 µsec (PAL)
LCD TYPE ST:
t = 1.50 ± 0.10 µsec (NTSC)
t = 2.40 ± 0.10 µsec (PAL)
Note: Refer to "1-5-1. LCD type check" for the discrimination of the LCD
type.
Menu setting:
VIDEO OUT of SET UP menu ............................................ NTSC
(This adjustment must be performed in NTSC mode, so don't set
the menu setting to "PAL".)
Adjusting method:
1) Select page: 0, address: 01, and set data: 01.
2) Change the data of page: D, address: D7, and adjust the phase
difference time (t) to the NTSC specified value.
3) Press the PAUSE button of the adjustment remote commander.
4) Change the data of page: D, address: DD, and adjust the phase
difference time (t) to the PAL specified value.
5) Press the PAUSE button.
6) Select page: 0, address: 01, and set data: 00.
CH1
CH2
Enlargment
CH1
CH2
t
Fig. 5-1-22.
H

3. Black Limit Adjustment (PK-52 board)

Set the amplitude of the VIDEO signal for driving the LCD to the
specified value. If deviated, the screen image will be blackish or
saturated (whitish).
Mode
Signal
Measurement Point
Measuring Instrument
Adjustment Page
Adjustment Address
Specified Value
Note: Refer to "1-5-1. LCD type check" for the discrimination of the LCD
type.
Adjusting method:
1) Select page: 0, address: 01, and set data: 01.
2) Select page: 5, address: F1, set data: 03.
3) Select page: D, address: D0, set data: 20.
4) Select page: D, address: D5, change the data and set the voltage
(A) between the reversed waveform black limit level and non-
reversed waveform black limit level to the specified value.
5) Press the PAUSE button of the adjustment remote commander.
6) Perform "Bright Adjustment".
7) Select page: 0, address: 01, and set data: 00.
A
Black limit level
5-33
PLAY
Arbitrary
Pin 9 of CN803 of FC-72 board
(VG)
External trigger: Pin 8 of CN803 of
FC-72 board (COM)
Oscilloscope
D
D5
LCD TYPE SA: A = 7.4 ± 0.1 V
LCD TYPE ST: A = 8.0 ± 0.1 V
Black limit level
2H
Fig. 5-1-23.