Checking Rgb Output B; Checking S Video Output S-C; Checking S Video Output Dc Level - Sony DVP-S7700 Service Manual

8. Checking RGB Output B

(MB-84 board) (AEP, UK model)
<Purpose>
This checks RGB output B. If it is incorrect, pictures will not be
displayed correctly in spite of connection to the TV with an EURO
AV connecting cord.
Video Encoder (IC252) check in test
Mode
mode menu "0" Syscon Diagnosis
Signal Color bars
EURO AV 1 (RGB)-TV connector
Test point
7 pin (75 Ω terminated)
Instrument Oscilloscope
Specification 700 ± 30 mVp-p
Checking method:
1) Confirm that the B-Y level is 700 ± 30 mVp-p.
Figure 7-9
9. Checking S Video Output S-C (MB-84 board)
<Purpose>
This checks whether the S-C satisfies the NTSC Standard. If it is
not correct, the colors will be too dark or light.
Video Encoder (IC252) check in test
Mode
mode menu "0" Syscon Diagnosis
Signal Color bars
CN252 !™ pin
Test point
Instrument Oscilloscope
Specification 286 ± 20 mVp-p
Connection:
100µF
+
75Ω
100k
±1%
±1%
Checking method:
1) Confirm that the S-C burst is 286 ± 20 mVp-p.
Figure 7-10
700 ± 30 mVp-p
CN252
12
Oscilloscope
11
286 ± 20 mVp-p
10. Checking S Video Output DC Level (MB-84 board)
<Purpose>
This checks signals for S1 and S2 compatible TV. If they are not
correct, the TV will not switch automatically to letter box, etc.
Mode
Signal
Test point
Instrument
Specification
Connection:
100µF
+
75Ω
100k
±1%
±1%
Checking method:
1) In the test mode initial menu "0" Syscon Diagnosis, select S-
terminal 0 V.
Confirm that the voltage at CN252 !™ pin is 0 Vdc.
2) Press any key to select S-terminal 5 V.
Confirm that the voltage at CN252 !™ pin is 5.0
7-4
Video Encoder (IC252) check in test
mode menu "0" Syscon Diagnosis
Color bars
CN252 !™ pin
Digital voltmeter
S-terminal 0 V: 0 Vdc
+0
S-terminal 5 V: 5.0 Vdc
–1.5
CN252
12 Digital voltmeter
11
+0
–1.5
Vdc.