Philips 7629, Service Manual

Page: 49 / 374

Vg2 Adjustment
1. Enter SDAM:
2. Press the following key sequence on the remote control transmitter:
0-6-2-5-9-6-MENU
Do not allow the display to time out between entries while keying the sequence.
3. Use the MENU UP/DOWN keys to highlight the WHITE TONE sub menu.
4. Press the MENU LEFT or MENU RIGHT key to enter the WHITE TONE sub menu.
5. In the WHITE TONE sub menu, press the MENU UP/DOWN keys to select NORMAL
RED, NORMAL GREEN, or NORMAL BLUE.
6. Use the MENU LEFT/RIGHT keys to set the values of NORMAL RED, NORMAL
GREEN and NORMAL BLUE to 40.
7. Press the MENU button twice to enter the normal user menu.
8. In the normal user menu, use the MENU UP/DOWN keys to highlight the PICTURE
sub menu (if necessary).
9. Press the MENU LEFT/RIGHT keys to enter the PICTURE sub menu.
10. Use the MENU UP/DOWN keys to select PICTURE. Be sure to record the current
value of PICTURE.
11. Use the MENU LEFT/RIGHT keys to set the value of PICTURE to zero.
12. Use the MENU UP/DOWN keys to select BRIGHTNESS. Be sure to record the current
value of BRIGHTNESS.
13. Use the MENU LEFT/RIGHT keys to set the value of BRIGHTNESS to minimum (OSD
just visible in a dark room).
14. Press the MENU button twice to return to the top level SDAM menu.
15. Press the STATUS/EXIT button to hide the SDAM onscreen display.
16. Connect the RF output of a video pattern generator to the antenna input.
17. Input a "black picture" test pattern to the television set.
18. Set the oscilloscope to 50 V/div and the time base to 0.2 milliseconds (external
triggering on the vertical pulse).
19. Ground the scope at the CRT panel and connect a 10:1 probe to one of the cathodes
of the picture tube socket (see schematic diagram B).
20. Measure the cut off pulse during first full line after the frame blanking (see Fig. 8-2).
You will see two pulses, one being the cut off pulse and the other being the white drive
pulse. Choose the one with the lowest value; this is the cut off pulse.
21. Select the cathode with the highest VDC value for the alignment. Adjust the V Cut-Off
of this gun with the SCREEN potentiometer (see Fig. 8-1) on the LOT to the correct
value (see table below).
22. Press the STATUS/EXIT button to display the SDAM onscreen display.
23. Press the MENU button to enter the normal user menu.
24. In the normal user menu, use the MENU UP/DOWN keys to highlight the PICTURE
sub menu (if necessary).
25. Press the MENU LEFT/RIGHT keys to enter the PICTURE sub menu.