Canon D78-5132, Service Manual

Page: 64 / 134

2.3 PC-Offset Adjustment
1. Receive the 16-step gray scale computer signal.
2. Set to
COMPUTER mode.
[R-Offset adjustment]
3. Connect an oscilloscope to test point “TP2211R” (+) and chassis ground (-).
4. Enter to the service mode, select item no. “275” and change data value to adjust the
pedestal level and black level to be same level.
[G-Offset adjustment]
5. Connect an oscilloscope to test point “TP2221G” (+) and chassis ground (-).
6. Select item no. “276” and change data value to adjust the pedestal level and black
level to be same level.
[B-Offset adjustment]
7. Connect an oscilloscope to test point “TP2231B” (+) and chassis ground (-).
8. Select item no. “277” and change data value to adjust the pedestal level and black
level to be same level.
2.4 PC Gain Adjustment
1. Receive the 16-step gray scale computer signal.
2. Set to
COMPUTER
mode.
[PC-R gain adjustment]
3. Connect an oscilloscope to test point “TP2211R” (+) and chassis ground (-).
4. Enter to the service mode, select item no. “30” and change data value to adjust “a” to
be 1.05 ±0.01Vp-p.
[PC-G gain adjustment]
5. Connect an oscilloscope to test point “TP2221G” (+) and chassis ground (-).
6. Select item no. “273” and change data value to adjust “a” to be 1.05 ±0.01Vp-p.
[PC-B gain adjustment]
7. Connect an oscilloscope to test point “TP2231B ” (+) and chassis ground (-).
8. Select item no. “274” and change data value to adjust “a” to be 1.05 ±0.01Vp-p.
Part 3: Adjustment
3-8
Pedestal level = Black level
Fig. 3-2