Main / Sub Color Level & Crt Cutoff - Mitsubishi WS-55517 Service Manual

MODELS: WS-55517 / WS-65517 / WS-73517
[Video Circuit]
3. Main/Sub Color Level
Measuring
Oscilloscope
Instrument
JA pin 29 & JA pin 37
Test Point
JB pin 5
------
Ext. Trigger
Measuring
------
Range
Input Signal
Color Bars
Input Terminal
Video
CIRCUIT ADJUST MODE
Activate ........ MEN U-2-4-5-7
Function ... ......... .....AUD IO
Item No. ...... ...........VIDEO
Adjus t Data ...........AD JU ST
Save Data .... ......... ENTER
Exit ......... .....MEN U (twice)
[CRT Circuit]
4. CRT Cutoff
Measuring
Oscilloscope
Instrument
Test Point TP6R, TP6G, TP6B
Ext. Trigger ------
Measuring
50V/Div. 2msec/Div.
Range
Input Signal
None
Input Terminal
Video Input
VC Function
Ite m Abbr.
1 SBRT
2 SCT
3 SCON
4 RDRH
5 GDR
6 BDRH
7 CTRH
8 CTGH
9 CTBH
Purpose:
Symptom:
1. Supply an NTSC signal to an External Video Input.
2. Select the NTSC signal as the source for both the main and sub pictures.
3. Connect an oscilloscope to connector JA pin 29 (Main Pr).
4. Activate the Adjustment mode.
5. Select Item "04 COLM" in the Main Matrix Function.
6. Adjust data so the PR signal is 0.66 Vp-p min. - 0.71 Vp-p max.
(If it cannot be adjusted within this range, set to the lower value)
7. Connect an oscilloscope to connector JA pin 44 (Sub Pr).
8. Select item "04 COLS" in the Sub Matrix Function.
9. Adjust so Sub PR = Main PR (+0.0V ~ -0.05V).
Purpose
Symptom:
Note: Use the Expand mode (full screen)
1. Select an External Input with no signal.
2. Enter the Adjustment Mode, VC Function.
3. Press "1", automatically blanks the screen and sets COL to 0.
Note: If the screen goes blue, turn off Video Mute.
4. Set the data to the values given in the table below.
5. Connect the oscilloscope to TP6R.
6. Adjust the Red Screen VR so the black level is 175V, as shown below, or
179V ±1VDC using an DC Voltmeter.
7. Repeat Steps 4 and 5 to set the Blue and Green Screen VRs, using
TP6G and TP6B.
Note: White Balance must be performed
Se tting
after this adjustment.
20
31
7
31
37
31
31
25
31
To match the sub picture color to that of the main picture.
Main and sub pictures colors differ.
To set the cutoff point for all three CRTs.
Monochrome has a color tint, or incorrect brightness.
Page 28
CIRCUIT ADJUST MODE
Activate ........ MEN U-2-4-5-7
Function ... ......... .....AUD IO
Item No. ...... ...........VIDEO
Adjus t Data ...........AD JU ST
Save Data .... ......... ENTER
Exit ......... .....MEN U (twice)