Monday, January 26, 2015

EMERSON EPT427 SERVICE MODE AND POWER SUPPLY CIRCUIT

    
          SERVICE MODE AND POWER SUPPLY CIRCUIT
Service mode:

1.Use the service remote control unit.
2.Turn the power on. (Use main power on the TV unit.)
3.Press " SLEEP " button on the service remote control unit. Version of micro computer will display on the CRT. (Ex: 5Y10-1.34)
4.Check the display on the lower left is "4A" and if it is not "4A", set it at "4A" according to "3-1 FRENCH, STEREO TYPE, ACCESS CODE, VIDEO TONE, SB SOUND" and "COMB FILTER".

+B Adjustment
Purpose:
To obtain correct operation. Symptom of Misadjustment: The picture is dark and the unit does not operate correctly.
1.Connect DC Volt Meter to TP601 and TP300(GND).
2.Adjust VR661 so that the voltage of TP601 becomes +138V±0.5V DC.

V. Size Adjustment
Purpose:
To obtain correct vertical width of screen image. Symptom of Misadjustment: If V. Size is incorrect, vertical size of image on the screen may not be properly displayed.
1.Operate the unit for at least 20 minutes.
2.Enter the Service mode.
3.Receive the Monoscope Pattern.
4.Press " 9 " button on the Service remote control unit and select " V-S "mode. (Display changes " V-S " and " V-P " cyclically when " 9 " button is pressed).
5.Press " CH up / down " buttons on the Service remote control unit so that the monoscope pattern will be 90±5% of display size and the circle is round.
6.Turn the power off and on again. (Main power button on the TV unit.)

V. Position Adjustment
Purpose:
To obtain correct vertical width of screen image. Symptom of misadjustment: If V. Position is incorrect, vertical height of image on the screen may not be properly displayed.
1.Operate the unit for at least 20 minutes.
2.Enter the Service Mode. (See page 5-1)
3.Receive the Monoscope Pattern.
4.Press " 9 " button on the Service remote control unit and select " V-P "mode. (Display change " V-S " and " V-P " cyclically when " 9 " button is pressed).
5.Press " CH up / down " buttons on the Service remote control unit so that the top and bottom of the mono scope pattern will be equal of each other.
6.Turn the Power off and on again. (Main power button on the TV unit.)

H. Position Adjustment
Purpose:
To obtain correct horizontal position of screen image.
Symptom of Misadjustment: If H. Position is incorrect, horizontal position of image on the screen may not be properly displayed.
1.Operate the unit for at least 20 minutes.
2.Enter the Service mode. (See page 5-1)
3.Receive the Monoscope Pattern.
4.Press " 8 " button on the remote control unit and select " H-P "mode.
5.Press " CH up / down " buttons on the Service remote control unit so that the monoscope pattern will be 90±5% of display size and the circle is round.
6.Turn the Power off and on again. (Main power button on the TV unit.)

H. Size Adjustment
Purpose:
To obtain correct horizontal size of screen image.
 Symptom of Misadjustment: If H. Size is incorrect, horizontal size of image on the screen may not be properly displayed.
1.Operate the unit for at least 20 minutes.
2.Receive the Monoscope Pattern.
3.Adjust VR561 so that the monoscope pattern will be 90±5% of display size and circle is round.
4.Turn the Power off and on again. (Main power button on the TV unit.)

PIN Cushion Adjustment
Purpose:
To obtain correct straight vertical line of screen image.
Symptom of Misadjustment: If H.Pin cushion is incorrect, vertical line of image on the screen may not be properly displayed.
1.Operate the unit for at least 20 minutes.
2.Receive the Cross hatch Pattern.
3.Adjust VR562 so that the cross hatch pattern will be straight line of display.
4.Turn the Power off and on again. (Main power button on the TV unit.)

Cut-off Adjustment
Purpose:
To adjust the beam current of R, G, B, and screen voltage.
Symptom of Misadjustment: White color may be reddish, greenish or bluish.
1.Degauss the CRT and allow CRT to operate for 20 minutes before starting the alignment.
2.Input the Black Raster Signal from RF Input.
3.Enter the Service mode. (See page 5-1)
4.Press " VOL down " button on the Service remote control unit and select " C/D " mode. (Display changes " C/D ", "VCO ", " 7F " and " FRENCH ", "STEREO TYPE", "ACCESS CODE", "VIDEO TONE", "SB SOUND" and "COMB FILTER" cyclically when " VOL
DOWN  " button is pressed.) then press " 1 ". The display will momentarily show " CUT OFF R " (R= Red). Now there should be a horizontal line across the center of the picture tube. If needed gradually turn the screen control on the flyback, clockwise until the horizontal line appears. Adjust the Red Cut off by pressing the " CH up / down  " buttons. Proceed to Step 5 when the Red Cut off adjustment is done.
5.Press the " 2 "button. The display will momentarily show " CUT OFF G " (G=Green). Adjust the Green Cut off by pressing the " CH up  / down  " buttons. Proceed to step 6 when the Green Cut off adjustment is done.
6.Press the " 3 " button. The display will momentarily show " CUT OFF B " (B=Blue). Adjust the Blue cut off by pressing the " CH up / down  " buttons. When done with steps 4, 5 and 6 the horizontal line should be pure white if not,then attempt the Cut off adjustment again.

White Balance Adjustment
Purpose:
To mix red, green and blue beams correctly for pure white.
Symptom of Misadjustment: White becomes bluish or reddish.
1.Operate the unit more than 20 minutes.
2.Face the unit to east. Degauss the CRT using Degaussing Coil.
3.Input the White Raster (APL 100%).
4.Set the color analyzer to the CHROMA mode and after zero point calibration, bring the optical receptor to the center on the tube surface (CRT).
5.Enter the Service mode . Press " VOL down " button on the Service remote control unit and select " C/D " mode. (Display changes " C/D ", "VCO ", " 7F " and " FRENCH ", "STEREO TYPE", "ACCESS CODE", "VIDEO TONE", "SB SOUND" and "COMB FILTER" cyclically when " VOL down  " button is pressed.) then Press No. 8 button on the Service remote control Unit.
6.Press No. 4 button on the service remote control unit for Red adjustment. Press N0. 5 button on the Service remote control unit for Blue adjustment.
7.In each color mode, Press " CH up / down " button to adjust the values of color.
8.Adjusting Red and Blue color so that the tempreture becomes 9200K (x : 286 / y : 294) ±3%.
9.At this time, Re-check that Horizontal line is white. If not, Re-adjust Cut-off Adjustment until the Horizontal Line becomes pure white.
10.Turn off and on again to return to normal mode. Receive APL 100% white signal and Check Chroma temperatures become 9200K (x : 286 / y : 294) ±3%.
Note: Confirm that Cut Off Adj. is correct after this adjustment, and attempt Cut Off Adj. if needed.