Signal Center Adjustment; Pc/Av Gamma Off Adjustment - Canon LV-7105 Service Manual

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.
(a)
Fig. 3-7
3-11
Part 3: Adjustment