Electrical Adjustment; Standard Video Level; Vcom Dc Level - Sony DVP-FX850 Service Manual

This section describes procedures and instructions necessary for
adjusting electrical circuits in this set.
Instruments required:
1) Color monitor TV
2) Oscilloscope 1 or 2 phenomena, band width over 100 MHz,
with delay mode
3) Frequency counter (over 8 digits)
4) Digital voltmeter
5) Standard commander (RMT-D183)
6) DVD reference disc
HLX-501 (J-6090-071-A) (dual layer) (NTSC)
HLX-503 (J-6090-069-A) (single layer) (NTSC)
HLX-504 (J-6090-088-A) (single layer) (NTSC)
HLX-505 (J-6090-089-A) (dual layer) (NTSC)
HLX-506 (J-6090-077-A) (single layer) (PAL)
HLX-507 (J-6090-078-A) (dual layer) (PAL)
SECTION 8

ELECTRICAL ADJUSTMENT

8-1. STANDARD VIDEO LEVEL

1. Checking Video Output Level
<Purpose>
This checks whether Video Output level satisfy the NTSC stan-
dard. If it is not correct, the brightness will be too large or small.
Mode
Signal
Measurement Point
Measuring Instrument
Specification
Checking method:
1) Confirm that the Video Output level is 1.00

8-2. VCOM DC LEVEL

1. VCOM DC Level Adjustment
<Purpose>
When the Driver Board or LCD is replaced, the VCOM DC Level
Adjustment is necessary.
Mode
Signal
Measurement Point
Measuring Instrument
Specification
Adjusting method:
1) Adjust the VR1 to attain 4.0 V to 4.1 V.
8-1
Play
Check the Color-bar (100%) signal
on DVD reference disc
LINE OUT (VIDEO) connector
(75 terminated)
Oscilloscope
1.00 0.05 Vp-p
Figure 8-1
Play
Arbitrary
VCOM (Driver Board)
Digital voltmeter
4.0 V to 4.1 V
DRIVER BOARD (SIDE A)
VR1
+
VCOM
Figure 8-2
DVP-FX850
0.05 Vp-p.
1.00 0.05 Vp-p