Canon D78-5132, Service Manual

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2.8 Signal Center Adjustment
1. Receive the 16-step gray scale computer signal.
2. Set to
COMPUTER mode.
[R-signal cneter adjustment]
3. Connect a digital voltmeter to test point “TP501R” (+) and chassis ground (-).
4. Adjust voltage to be 7.30 ±0.05V by using VR503.
[G-signal cneter adjustment]
5. Connect a digital voltmeter to test point “TP503G” (+) and chassis ground (-).
6. Adjust voltage to be 7.30 ±0.05V by using VR533.
[B-signal cneter adjustment]
7. Connect a digital voltmeter to test point “TP505B” (+) and chassis ground (-).
8. Adjust voltage to be 7.30 ±0.05V by using VR563.
2.9 PC/AV Gamma Off Adjustment
[PC-gamma off adjustment]
1. Receive the 16-step gray scale computer signal.
2. Set to
COMPUTER mode.
3. Connect an oscilloscope to test point “TP503G” (+) and chassis ground (-).
4. Enter to the service mode, select item no. “0” and change data value to adjust “a” to
be 1.40 ±0.01Vp-p.
[AV-gamma off adjustment]
5. Receive the 16-step gray scale video signal.
6. Set to
VIDEO mode.
7. Connect an oscilloscope to test point “TP503G” (+) and chassis ground (-).
8. Enter to the service mode, select item no. “0” and change data value to adjust “a” to
be 1.40 ±0.01Vp-p.
Note:
* This adjustment should be carried out before adjusting PC/AV-Video Adjustment-1
and 2.
Part 3: Adjustment
3-11
Fig. 3-7
(a)