Black Reference Adjustment; Common Center Adjustment - Canon LV-7215U Service Manual

Part 3: Adjustment

2.10 Black Reference Adjustment

1. Receive the 16-step grey scale computer signal with Computer2 [RGB] mode.
2. Enter the service mode.
3. Connect an oscilloscope to test point "TPG1" (+) and chassis ground (–).
4. Select group no. "10", item no. "3" and change data value to adjust amplitude "a" to
be 9.8 ± 0.1V.
5. Connect an oscilloscope to test point "TPR1" (+) and chassis ground (–).
6. Select item no. "4" and change data value to adjust amplitude "a" to be 9.8 ± 0.1V.
7. Connect an oscilloscope to test point "TPB1" (+) and chassis ground (–).
8. Select item no. "5" and change data value to adjust amplitude "a" to be 9.8 ± 0.1V.

2.11 Common Center Adjustment

1. Receive the 1 line black/white pattern computer signal with Computer2 [RGB] mode.
2. Enter the service mode.
3. Project only green light component to the screen.
4. Select group no. "10", item no. "9" and change data value to obtain the minimum
flicker on the screen.
5. Project only red light component to the screen.
6. Select item no. "10" and change data value to obtain the minimum flicker on the
screen.
7. Project only blue light component to the screen.
8. Select item no. "11" and change data value to obtain the minimum flicker on the
screen.
black level
(a)
black level
Fig. 3-9
3-16