Remove the picture tube, found the header focus copper has born patina. Measurement with multimeter R x 10 k Ω focus there are about 4 m Ω pole of resistance (normal should be up big), has the leakage. After a new header, the image is clear. fNqservice manual download site
Off the boot, the color, see black and white images still partial color. Shutdown, found R804 (R - BKG), R809 (B - DRIVE) has been bad. After renewals, follow these steps to reset: (1) the boot, turn off the color. (2) to adjust the white balance of five trimmer potentiometer, namely three dark white balance R804 (R - BKG), R807 (G - BKG), R811 (B - BKG) and two bright white balance R802 (R - DRIVE), R809 (B - DRIVE), potentiometer, all spin counterclockwise to the end. (3) adjust the accelerating voltage knob, made the brightest when the screen is not dazzling, free of flyback lines; When the dark image faintly visible. (4) adjust focus voltage knob, most make the image clear as well. (5) in the bright screen abject in bright white balance adjustment, adjust the R802 and R809, try to bring up the pure without color of black and white image. (6) in low dark dark screen white balance adjustment, fine tuning three dark white balance potentiometer R804, R807, R811, faintly visible image without color, same as pure black and white image. (7) check under high and low brightness, if the image is without any color, pure black and white image. If yes, which adjusted the; If not, be reset. Finally add color, image color is no longer unusual, returned to normal. fNqservice manual download site
The multimeter to R x 10 Ω block, with red pens and grounding, black table touch touch check audio circuit. Table touch touch C420 silent when the cathode, touch C425 remained silent when the cathode, check no damage for speakers. Welding under T421 output transformer inspection, found that the primary has broken. After replacing T421 boot, audio sound small and clip has burst noise. Will C420 end from circuit break open, there is still a burst of noise, specify in the audio power amplifier circuit. Welding C425 output coupling capacitance under inspection, the charge and discharge is normal, no damage, welding on again. When turned by hand touch the filter capacitor C424, feel temperature, welding inspection, found the capacitor leakage is serious. Replace a 22 u F / 160 v after electrolytic capacitor, troubleshooting.

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