Philips 7603 series, Руководство по обслуживанию

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5. Return to the SAM via the MENU key.
6. Connect the RF output of a pattern generator to the antenna input. Test pattern is a 'black' picture (blank screen on CRT
without any OSD info).
7. Set the channel of the oscilloscope to 50 V/div and the time base to 0.2 ms (external triggering on the vertical pulse).
8. Ground the scope at the CRT panel and connect a 10:1 probe to one of the cathodes of the picture tube socket (see
diagram B).
9. Measure the cut off pulse during first full line after the frame blanking (see Fig. 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.
10. Select the cathode with the highest V
DC
value for the alignment. Adjust the V
cutoff
of this gun with the SCREEN
potentiometer (see Fig. 1) on the LOT to the correct value (see table below).
11. Restore BRIGHTNESS and CONTRAST to normal (= 31).
Fig. 2
Focusing
1. Tune the set to a circle or crosshatch test pattern (use an external video pattern generator).
2. Choose picture mode NATURAL (or MOVIES) with the 'SMART PICTURE' button on the remote control transmitter.
3. Adjust the FOCUS potentiometer (see Fig. 1) until the vertical lines at 2/3 from east and west, at the height of the
centerline, are of minimum width without visible haze.