When the grating brightness changes, observe the geometry size of grating and receive the sticker position did not change and displacement of TV programs, and has been normal color and sound. Preliminary judgment according to the observation of fault phenomena, failure positions in brightness or visual circuit part. Boot monitor switch power supply output voltage of + B, there is no change to monitor visual + 180 v power supply voltage, + 180 v voltage drop when failure occurs, the fault level is put in apparent power supply part. The + 180 v is by the line output transformer output pulse voltage (foot, D406 rectifier, current limiting R443, C447 supply after filtering. Detection D406, R443 normal, remove the C447 (10 mu F / 400 v) test, found a pin with corrosion phenomenon. After the replacement, troubleshooting.Md5service manual download site