Sub-Y Gain - Mitsubishi Electric HD-4001 Service Manual

[Video Circuit]

2. Sub-Y Gain

Measuring
Oscilloscope
Instrument
TPSY
Test Point
Ext. Trigger ------
Measuring
-------
Range
Input Signal
Color bars
Input Terminal
External Input
[Video Circuit]
3. Sub Picture Offset
Measuring
----
Instrument
----
Test Point
Ext. Trigger
------
Measuring
-------
Range
Input Signal
Full White Raster
Input Terminal
External Input
MODEL: HD-4001
Purpose: To set the sub picture Y level
Incorret analog source sib picture brightness level.
Symptom:
1. Supply a Color Bars with 100% white signal to an External Input. Select this
input as the sub picture source.
2. Connect a scope to TPSY.
3. Enter the Alignment Mode (MENU-2-4-5-7)
4. Select the SMTX function (AUDIO button).
5. Select adjust item #14 YDRS (VIDEO button).
6. Set the data so the waveform at TPSY equals the main-y signal. (ADJUST
buttons).
7. Press "ENTER" to save data.
8. Press "MENU" twice to exit the service mode.
TPSY
Purpose:
To match sub picture white to main picture white
Symptom:
Sub picture white differs from white in the main picture.
1. Supply a full white raster signal to an External Input.
2. Select the white raster as the source for both the main and sub pictures.
3. Use the PIP/POP buttion to select the Single PIP mode.
4. Enter the Alignment Mode (MENU-2-4-5-7)
4. Select the AD9883A function (AUDIO button).
5. Select item #12 ROFF and #14 BOFF (VIDEO button).
6. Set the data fore items #12 and #14 so the sub picture white is close to that in
the main picture. (ADJUST buttons).
7. Press "ENTER" to save data.
8. Press "MENU" twice to exit the service mode.
Page 19
PWB-SIGNAL (Partial)
TPY