A preliminary analysis of the R - Y synchronous demodulator, RGB matrix or put bad output circuit. Fault occurs, the use of multimeter measuring R, G, B amplifier tube voltage of 97.5 V c, each tube B voltage 84 V, 7.8 V, 7.6 V respectively. That red tube b extremely high voltage 0.6 V, results in the decrease of its c more potential, red gun beam increases, at the same time make Y end potential to rise. Measuring M51393AP (20) feet (R - Y) voltage of 8.45 V, check its peripheral components are normal. VMAservice manual download site
 VMAservice manual download site
The foot from the PCB welding measurement. The voltage is 8.45 V, thus concludes that the foot internal R - Y channel has local damage. Because of the integrated block most function is good, its price is higher, so, with the emergency repair, in between (20) feet and to access a 15 k Ω fine-tuning potentiometer, electricity, adjust the potentiometer (20) feet, voltage drop to normal around 7.8 V. Observe the screen color returned to normal. Remove the potentiometer measured its resistance value is 4.9 k Ω, at this time with a 5.1 k Ω fixed resistor after the substitution of commissioning. Color effect is good.VMAservice manual download site