Found in the boot of a distinct violet electronic kinescope, that has been damaged tube, horizontal deflection to the series resistance of the r554 circuit board (100/1w) red smoke, indicating that the scanning part is not working properly. To find out what causes damage to the tube, it adopts the following methods: off line tube power supply, power supply for measurement of normal 110V, the power supply is normal; remove deflection coil plug c0-4, start with 500 universal pressure test bar, measure a high-pressure cap voltage has been playing table, more than 30000 V, and have obviously felt the strong high pressure discharge ionization air sound, while the voltage is normal in didn't listen to a deflection coil pressure cap is generally only about 15000 volts. Will be part of all easy to weld local re welding again, remove weld may, with the frequency shift digital meter measuring frequency up to 18.6k, ic501 (an5435) the pin voltage is almost normal, replace all the capacitor row oscillation part and the AFC part of the invalid, when the measuring frequency adjust potentiometer is R505 (1K) at both ends resistance, found that this is less than 1K (with resistor r507[2.7k] in parallel), while 2.7K, R505 has open circuit damage, replace, starting pressure cap no electroacoustic put obviously, the measured voltage is only 15000 volts, insert deflection coil, the voltage is 25000 v. Found this fault. This fault is rare, a potentiometer, but the resulting loss is enormous: the big picture tube.yZPservice manual download site