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File name CHASSIS 14.1 ELECTRICAL ADJUSTMENTS.pdf

CHASSIS 14.1 ELECTRICAL ADJUSTMENTS 1.1. Supply Voltage Adjustment Connect a digital voltmeter to the cathode of diode D611 at the AV1 mode of the TV and set the screen voltage to the minimum with the screen potentiometer. Adjust the main supply voltage (B+) with P601 potentiometer to the following value (after adjustment, readjust Screen voltage). 20" : 119 VDC 21" : 116 VDC (117 VDC for A51EAL155X01) 25" : 145 VDC 28" : 145 VDC (147 VDC for A66EAK071X11) 28" Pure Flat 16/9 : 140 VDC 28" Super Flat 16/9 : 140 VDC 29" : 125 VDC 32" Pure Flat 16/9 : 140 VDC 32" Super Flat 16/9 : 131 VDC 33" : 158 VDC 2. SERVICE ADJUSTMENTS You need the special service remote control to enter and exit the service menu of the TV (you can order it from the manufacturer). All buttons of the Service RC are same with the user remote control, only service menu In / Out is added to it (please see the picture below). Navigation Service In/Out P+ / PV+ / VOK : Enters to / exits from the Service Menu : Moves upward / downward inside the menu : Changes the values or options : Changes the brightness, contrast values to 00, 3F and preset values sequentially (Its OSD is shown). When P+ / P- buttons pressed the service menu is re shown. arizanotlari.com 2.1. AGC Adjustment · · · Apply an RF signal with amplitude 65±1 dBuV to the antenna input of TV with a pattern generator (switch sound carrier to Off and switch "Video Ext" to On). Switch on the Service Menu with the Service RC and find the AGC with P+ / P- buttons. Measure the 38.9 MHz signal on pin 11 (IF) of Tuner with an oscilloscope. Adjust "AGC" to get following values: Secam LL' (Stereo) or PAL I Non-multimedia : 500 ± 20 mVpp PAL I Multimedia : 600 ± 20 mVpp Secam LL' (Mono) : 350 ± 20 mVpp PAL/SECAM BG Dolby Prologic : 550 ± 20 mVpp Other versions : 220 ± 20 mVpp Exit from the service menu with the Service RC. · 2.2. Screen Adjustment · · · · · · Select Brightness to 32, Contrast to 40 and Saturation to 20. Enter the Service Menu with the Service RC and select "SCRN" option with P+ / P- buttons and switch to ON with V+ / V- button. For 29" sets press "OK" button afew times in the "SCRN" item to get "BRI 00" on the screen. Adjust the screen potentiometer to the level where the screen is just black (For 29" sets press "OK" button to get "BRI32"). By pressing one of V+ / V- buttons, get the picture (SCRN is switched to Off). Exit from the Service menu. 2.3. Geometry Adjustments · · · · · · · · · · · Apply a FUBK or Philips Test pattern. Enter Service Menu with Service RC and select "VSLP" option with P+ / P- buttons (In this option, the upper half part of the pattern is shown and lower half part is blanked). Adjust VZOM to 20 for 4/3 sets and 19 for 16/9 sets. Adjust VSCR to "1F" ("20" for 32" Super Flat 16/9) Adjust VSLP such that middle line of the pattern is cut. Adjust vertical position with VSHT, vertical linearity with SCOR and vertical height with VAMP. For 4/3 sets, adjust the horizontal amplitude with EWW. For