Symphonic WF2703 CRT TV - How to enter service mode – adjustments – SMPS and deflection circuit diagram - 27" CTV

Electrical adjustments are required after replacing circuit components and certain mechanical parts. It is important to perform these adjustments, after all repairs and replacements have been completed. Also, do not attempt these adjustments unless the proper equipment is available.

Test Equipment Required
1. NTSC Pattern Generator (Color Bar W/White Window, Red Color, Dot Pattern, Gray Scale, Monoscope, Multi-Burst)
2. DC Voltmeter
3. Oscilloscope: Dual-trace with 10:1 probe,
V-Range:0.001~50V/Div,
F-Range:DC~AC-60MHz
4. Plastic Tip Driver
5. Remote control unit:Part No. N0127UD or N0132UD or N0105UD or N0108UD
6. DC power supply 13.2V/5A
How to make Service remote control unit
1. Prepare normal remote control unit. (Part No. N0127UD or N0132UD or N0105UD or N0108UD)
Remove 3 Screws from the back lid. (Fig. 1-1)
2. Add J1 (Jumper Wire) to the remote control CBA. (Fig. 1-2)

DC 120V Adjustment
Purpose: To obtain correct operation.
Symptom of Misadjustment: The picture is dark and the unit does not operate correctly.
Note: TP601, TP300(GND), VR661 --- Main CBA
1. Connect DC Volt Meter to TP601 and TP300(GND).
2. Adjust VR661 so that the voltage of TP601 becomes +120±0.5V DC.

SMPS (Power Supply) and Deflection circuit diagrams [Click on the pictures to magnify]

CAUTION
Fixed voltage ( or Auto voltage selectable ) power supply circuit is used in this unit.  If Main Fuse (F601) is blown, check to see that all components in the power supply circuit are not defective before you connect the AC plug to the AC power supply. Otherwise it may cause some components in the power supply circuit to fail.

Service mode adjustments

Black Strech Control Adjustment
Purpose: To show the fine black color.
Symptom of Misadjustment: Black color will not appear correctly.
Note: Use Service remote control unit.
1. Enter the Service mode. (See page 5-1)
2. Press " 6 " button on the Service remote control unit. " B-S " is indicated.
3. Press " CH ▲/▼"buttons on the Service remote control unit so that display will change " OFF ", " 0", " 1 ", " 2 " and " 3 ". Then choose " B-S OFF ".
4. Press " 6 " button on the Service remote control unit. " B-S*2 " is indicated.
5. Press " CH ▲/▼" buttons on the Service remote control unit so that display will change " 0 " and " 1 ". Then choose " B-S*2 0".
6. Turn the power off and on again. (Main power button on the TV unit.).

Setting for 7F and FRENCH data Values

General

1. Enter the Service mode.

2. Press " VOL ▼" button on the Service remote control unit. Display changes " C/D ", " 7F ", " FRENCH

", " ACCESS CODE ", " STEREO ", " VIDEO TONE ", " FM-MODE ", and " V-OUT " cyclically when " VOL  ▼" button is pressed.

7F

1. Press " VOL ▼" button on the Service remote control unit. Then select 7F display.

2. Press " CH ▲/▼" buttons on the Service remote control unit. Then choose 7F=FF

FRENCH
1. Press " VOL ▼" button on the Service remote control unit. Then select FRENCH display.
2. Press " CH ▲/▼" buttons on the Service remote control unit. Then choose FRENCH=OFF.
ACCESS CODE ---- set to OFF
VIDEO TONE ---- set to ON
FM-MODE ---- set to OFF
V-OUT ---- set to OFF
STEREO ---- set to ON
Note: C/D and VCO data values do not need to be adjusted at this moment.

Setting for CONTRAST, COLOR, TINT, V-TINT and SHARP data Values
General
1. Enter the Service mode.
2. Press " MENU " button on the Service remote control unit. Display changes " BRIGHT ", " CONTRAST "," COLOR ", " TINT ", " V-TINT " and " SHARP "
cyclically when " MENU " button is pressed.
CONTRAST (CNT)
1. Press " MENU " button on the Service remote control unit. Then select " CONTRAST " (CNT) display.
2. Press " CH ▲/▼" buttons on the Service remote control unit so that the value of " CONTRAST "(CNT) becomes 84.
COLOR (CLR)
1. Press " MENU " button on the Service remote control unit. Then select " COLOR " (CLR) display.
2. Press " CH ▲/▼" buttons on the Service remote control unit so that the value of " COLOR " (CLR) becomes 58.

TINT (TNT)
1. Press " MENU " button on the Service remote control unit. Then select " TINT " (TNT) display.
2. Press " CH ▲/▼" buttons on the Service remote control unit so that the value of " TINT " (TNT) becomes 62.
V-TINT (V-TNT)
1. Press " MENU " button on the Service remote control unit. Then select " V-TINT " (V-TNT) display.
2. Press " CH  ▲/▼" buttons on the Service remote control unit so that the value of " V-TINT " (V-TNT) becomes 59

SHARP (SHARP)
1. Press " MENU " button on the Service remote control unit. Then select " SHARP " (SHARP) display.
2. Press " CH ▲/▼" buttons on the Service remote control unit so that the value of “ SHARP " (SHARP) becomes 47.
Note: BRIGHT data value does not need to be adjusted at this moment.
 Black Level Adjustment
Purpose: Set Black Level
Symptom of Misadjustment: 

If black level is incorrect, Proper brightness can not be obtained by adjusting the Brightness Control.

1. Enter the Service mode. 

2. Press " MENU " button on the Service remote control unit and select " BRT "mode. (Display changes " BRT ", " CNT ", " CLR ", " TNT ", " V-TNT ", and

" SHARP " cyclically when MENU button is pressed).

3. Press " CH ▲/▼" buttons on the Service remote control unit so that the value of " BRT " becomes 128.

4. Turn the power off and on again. (Main power button on the TV unit.)