This fault is usually caused by the malfunction of the scan circuit or the circuit of the picture tube.. When the repair time to open the electronic look like, with the use of a thousand meters check AN2510S's 2 foot and 12 foot whether there is 5V working voltage. No voltage should check whether the 5V switching power supply voltage output connector, whether good contact. Voltage is normal with oscilloscope check output tube collector Q702 whether flyback pulse signal output, should check Q701, Q702 whether the damage to and oscillation element Q712, Q714, VR702, C710 AN2510S 20 and 21 feet connected whether weld or open circuit. If the Q702 collector output line of the reverse pulse signal voltage waveform is normal, the fault is in the picture tube circuit. At this time, the application of the meter can detect the damage of the filament of the tube, and whether the high pressure anode and the anode voltage and the gate voltage are normal..P5bservice manual download site