Mitsubishi Electric LC62 CHASSIS XL6500LU, Руководство по обслуживанию

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[A/D Pre-Amplifi cation Circuit]
1. ADC offset/gain adjust-
ment
To adjust the DC level and amplitude of the video signal at the time of ADC input.
Solid black, solid white, or incorrect color phase appear in the projected im-
age.
Measuring
instrument
-----
Test point -----
EXT trigger
-----
Measurement
range
-----
Input signal
Shown in the table
below
Input terminal
COMPUTER 2
IN terminal
Adjustment purpose
Symptom when
incorrectly adjusted
* Enter the adjustment commands in capital alphanumeric letters.
1. Connect the projector with a PC running Microsoft
® Windows ® 95/98/Me/XP operat-
ing system. (Refer to the fi gure on page 1.)
2. Start Microsoft ® Windows ® 95/98/Me/XP.
3. Start the communication program [Hyper Terminal] on Microsoft ® Windows ® 95/98/
Me/XP to open the Hyper Terminal window. (Refer to Hyper Terminal Setting on
page 2 for the settings.)
Offset/gain adjustment with the RGB signal supplied
4. Supply an XGA signal (White/black raster No. 29).
5. Enter [00~5] (the command for RGB input offset/gain adjustment) on the Hyper Ter-
minal window, and the adjustment proceeds automatically.
6. When the adjustment fi nishes, the return command [00~5111] is displayed on the
Hyper Terminal window. The last three digits of the return command indicate the
adjustment results of R, G, and B respectively from the left by 1 or 0. When the
adjustment has succeeded, 1 is displayed. When it has failed, 0 is displayed. Pos-
sible causes of failures in the adjustment are errors on the PCBs, wrong signals,
and wrong input selection.
Offset adjustment with the component video signal supplied
7. Supply an NTSC signal (SMPTE (White), No. 30).
8. Enter [00~AC1] (the command for video input clamp adjustment) on the Hyper Ter-
minal window, and the adjustment proceeds automatically.
9. When the adjustment finishes, the return command [00~AC111] is displayed on
the Hyper Terminal window. The last two digits of the return command indicate the
adjustment results of CR and CB respectively from the left by 1 or 0. When the
adjustment has succeeded, 1 is displayed. When it has failed, 0 is displayed. Pos-
sible causes of failures in the adjustment are errors on the PCBs, wrong signals,
and wrong input selection.
Adjustment Procedures
No. Pattern
29 White/black raster
30 SMPTE (White)*
* Though the signal generator sup-
plies this signal as a green signal,
the projector receives it as Y/CB/CR
signal. Therefore, this signal is pro-
jected as a full white SMPTE signal.