JVC AV-20FD24 Service Manual

Also see for AV-20FD24: User guide User guide

Contents

No. 52133 23AV-20FD243. PURITY AND CONVERGENCEADJUSTMENTSNOTE1. Turn the unit on and let it warm up for at least 30 minutes beforeperforming the following adjustments.2. Place the CRT surface facing east or west to reduce theterrestrial magnetism.3. Turn ON the unit and demagnetize with a Degauss Coil.3-1: STATIC CONVERGENCE (ROUGH ADJUSTMENT)1. Tighten the screw for the magnet. Refer to the adjusted CRT forthe position. (Refer to Fig. 3-1)If the deflection yoke and magnet are in one body, untighten thescrew for the body.2. Receive the green raster pattern from the color bar generator.3. Slide the deflection yoke until it touches the funnel side of theCRT.4. Adjust center of screen to green, with red and blue on the sides,using the pair of purity magnets.5. Switch the color bar generator from the green raster pattern tothe crosshatch pattern.6. Combine red and blue of the 3 color crosshatch pattern on thecenter of the screen by adjusting the pair of 4 pole magnets.7. Combine red/blue (magenta) and green by adjusting the pair of 6pole magnets.8. Adjust the crosshatch pattern to change to white by repeatingsteps 6 and 7.3-2: PURITYNOTEAdjust after performing adjustments in section 3-1.1. Receive the green raster pattern from color bar generator.2. Adjust the pair of purity magnets to center the color on thescreen.Adjust the pair of purity magnets so the color at the ends areequally wide.3. Move the deflection yoke backward (to neck side) slowly, andstop it at the position when the whole screen is green.4. Confirm red and blue colors.5. Adjust the slant of the deflection yoke while watching the screen,then tighten the fixing screw.3-3: STATIC CONVERGENCENOTEAdjust after performing adjustments in section 3-2.1. Receive the crosshatch pattern from the color bar generator.2. Combine red and blue of the 3 color crosshatch pattern on thecenter of the screen by adjusting the pair of 4 pole magnets.3. Combine red/blue (magenta) and green by adjusting the pair of 6pole magnets.3-4: DYNAMIC CONVERGENCENOTEAdjust after performing adjustments in section 3-3.1. Adjust the differences around the screen by moving the deflec-tion yoke upward/downward and right/left.(Refer to Fig. 3-2-a)2. Insert three wedges between the deflection yoke and CRT funnelto fix the deflection yoke.(Refer to Fig. 3-2-b)Fig. 3-1DEFLECTION YOKEDEFLECTION YOKE SCREWMAGNET SCREW6 POLE MAGNETS4 POLE MAGNETSPURITY MAGNETSFig. 3-2-aR G BRGBR G BRGBUPWARD/DOWNWARD SLANT RIGHT/LEFT SLANTFig. 3-2-bWEDGE WEDGEWEDGEWEDGE POSITION