The camera to monitor display TV video output, found that obvious image edge in the double. Test input waveform B301 12 feet did not see abnormalities. Will be on the same camera (VEP23146B) board removed, replace with the similar machine board, troubleshooting, image display is normal, prove that the original machine digital video circuit there is a fault. dsiservice manual download site
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According to the failure phenomenon, combined with the circuit analysis is the image digital processing chip Y/C fault occurs. Because IC306 internal circuit is mainly responsible for Y/C separation and image contour line, field calibration, and the chip failure will directly affect the clarity of the image. Illustrated by image edge of ghosting, chip internal problems delay line. Potential of test IC306 each pin, found the potential below the normal stated value more. Access to the sawtooth wave generator. Test of 79 ~ 72 feet output waveform and tagging amplitude have bigger difference. The waveform sequence changed. So doubt IC306 defective, touch the chip's surface. A bit higher than other chip temperature. Therefore decided to replace the chip, the chip with cigarette tin foil with adhesive plaster, with phi enameled wire in side the lead through the 0.2 mm, with a high power of the hair dryer in the previous arrangement made with iron chip pin wide and narrow nozzle, blow on IC306 side pin 2 minutes. Then pull the enameled wire, make the pins away from the circuit board and remove the IC306, use new IC pointed iron welding. Check, boot to watch the image, the fault disappear, image quality is normal, and then prove that the maintenance approach is correct, there is no grief.dsiservice manual download site