BOXLIGHT MP-45, Service Manual

Page: 26 / 130

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Electrical Adjustments
1. Receive the 16-step gray scale computer signal with
Input 3 [video] mode.
2. Enter the service mode.
3. Connect an oscilloscope to test point “
TP531
” (+) and
chassis ground (-).
4. Select group no. “
4
”, item no. “
0
” and change data
value to adjust waveform “ a ” to be minimum ampli-
tude.
5. Connect an oscilloscope to test point “
TP561
” (+) and
chassis ground (-).
6. Select item no. “
1
” and change data value to adjust
waveform “ a ” to be minimum amplitude.
7. Connect an oscilloscope to test point “
TP501
” (+) and
chassis ground (-).
8. Select item no. “
2
” and change data value to adjust
waveform “ a ” to be minimum amplitude.
(a)
White Level
⁄4
Video Gain adjustment
1. Receive the 16-step gray scale computer signal with
Input 3 [Video] mode.
2. Enter the service mode.
3. Connect an oscilloscope to test point “
TP531
” (+)
and chassis ground (-).
4. Select group no. “
4
”, item no. “
12
” and change data
value to adjust amplitude “ a ” to be
9.8
±0.1V.
(a)
black level
black level
⁄5
Video black Level adjustment
1. Receive the black 0% component 480i video signal
with Input 3 [Component] mode.
2. Enter the service mode.
3. Select group no. “
5
”, item no. “
11
” and change data
value to adjust the green noise on the screen to the
deepest green.
⁄6
Component Y pedestal adjustment
1. Receive the white 100% component 480i video signal
with Input 3 [Component] mode.
2. Enter the service mode.
3. Select group no. “
5
”, item no. “
18
” and change data
value to adjust the magenta noise on the screen to
the deepest magenta.
⁄7
Component A/D reference voltage
(top side) adjustment
1. Receive the black 0% component 480i video signal
with Input 3 [Component] mode.
2. Enter the service mode.
3. Select group no. “
5
”, item no. “
12
” and change data
value to adjust the blue noise on the screen to the
deepest blue.
4. Select item no. “
13
” and change data value to adjust
the red noise on the screen to the deepest red.
⁄8
Component Cb/Cr pedestal adjustment
1. Receive the 16-step gray scale component 480i sig-
nal with Input 3 [Component] mode.
2. Enter the service mode.
3. Connect an oscilloscope to test point “
TP531
” (+) and
chassis ground (-).
4. Select group no. “
4
”, item no. “
0
” and change data
value to adjust waveform “ a ” to be minimum amplitude.
5. Connect an oscilloscope to test point “
TP561
” (+) and
chassis ground (-).
6. Select item no. “
1
” and change data value to adjust
waveform “ a ” to be minimum amplitude.
7. Connect an oscilloscope to test point “
TP501
” (+) and
chassis ground (-).
8. Select item no. “
2
” and change data value to adjust
waveform “ a ” to be minimum amplitude.
(a)
White Level
⁄9
Component Gain adjustment