This kind of failure is more power circuit and audio/visual decoding circuit has a problem caused by audio and video signal processing circuit of the power supply part of the machine is consist of IC1121, IC1111 and external components, respectively output + 5 V and + 3.3 V voltage, supply the mpeg-2 and AC - 3 decoder. Measuring IC1121 3 feet of + 3.3 V output voltage is about 1.5 V when failure occurs, the abnormal voltage will directly affect the mpeg-2 and AC - 3 the normal work of the decoder, cause no silent failure. Because of a malfunction is normal work after a while time, estimated at + 3.3 V power supply in the circuit components, electric work performance is bad, see figure 1. Check the capacitance C1114 is good, but found that boot after work, IC1111 five end voltage regulator block temperature rise quickly and on the high side, determine IC1111 bad performance. Change with the specifications of the integrated block IC1111, electricity of commissioning, troubleshooting.99Hservice manual download site