Panasonic CT-25G6E Service Manual

Also see for CT27G6DE - 27" COLOR TV: Operating instructions Service manual

Panasonic CT-25G6E Service Manual Manual pdf 11 page image

- 11 -Purity and Convergence ProcedureAdjustment is necessary only if the CRT or thedeflection yoke is replaced or if the setting wasdisturbed. The complete procedure consists of:1. Vertical Raster Shift Adjustment. (Only for Modelswith Purity/Convergence Assembly with 4 Pairs ofRings).2. Initial static convergence.3. Setting the purity.4. Final static convergence.When the CRT or the Yoke is ReplacedPlace the yoke on the CRT neck (do not tightenthe clamp).For a 2-piece assembly (see Fig. 5):Position purity/convergence assembly as shown andtighten clamp snugly. Remove the hot-melt glue sealon assembly and position like tabs of purity devicetogether at 12 o’clock to reduce its magnetic fieldeffect.For models using 4 pairs of rings, place the verticalraster shift tabs at 3 o’clock (90o from the purity andconvergence tabs, see Fig. 6 and Fig. 7).For a 1-piece assembly (see Fig. 8):Position like tabs of purity devices together at 12o’clock to reduce any magnetic field effect. (For betterresults, note part number and look for specifications atService Center)For either assemblies:Turn the Receiver ON. Operate the Receiver for 60minutes using the first Purity Check field (white screen)to stabilize the CRT.Fully degauss the Receiver by using an externaldegaussing coil.Slide the deflection yoke back and forth on the neck ofthe CRT until it produces a near white, uniform raster.Vertical Raster Shift Adjustment (Only forModelswithPurity/ConvergenceAssemblywith4Pairsof Rings).Apply a green pattern with a horizontal line, adjust theDeflection Yoke so that has no tilt, then secure it.Adjust center line of the pattern with the mechanicalcenter of the CRT, this center is determined by twomarks at the side edges of the screen. To adjust theline, once the vertical raster shift tabs are place at 3o’clock to reduce its magnetic field effect (see Fig. 6and Fig. 7) open the tabs the same angle from thecenter, until the center line of the pattern becomes astraight line, centered with the marks of the CRT. (seeFig. 9.)Initial Center Static ConvergenceConnect a dot/cross hatch generator to the Receiverand tune in a signal. Observe misconvergence atcenter of the screen only.Adjust the R & B pole magnets; by separating tabs androtating to converge blue with red.Adjust the R & B and R & B & G pole magnets: byseparating tabs and rotating to converge blue and red(magenta) with green.Note: Precise convergence at this point isnot important.Figure 5. Positioning of Purity/Convergence Assembly(2-piece assembly)Figure 6. Positioning of Purity/ConvergenceAssembly (4 Pairs of Rings)Figure 7. Positioning of Purity/ConvergenceAssembly (4 Pairs of Rings)Figure 8. Positioning of Purity/ConvergenceAssembly (1-piece assembly)Figure 9. Vertical Raster Shift Adjustment(4 pairs of rings assembly)