This machine works originally, moved to a new home after the open to clean up a health, appeared the next day turned on this kind of failure. Wired up observation, found on the front panel power light is dim, brightness is obviously not normal. Open the back cover to detect when the standby power supply, found that the tube to the ground of the stern plate was under pressure in the main circuit board, no and tail plate connection, to show that the main cleaning up after forget to connect the ground wire tube to end plate. See here the author developed a concern: the maintenance career for many years, the writer has experienced one of the few cases caused by tube to the ground fall off of the stern plate microprocessor breakdown damage failure. Good connection tube to the ground of the stern plate, boot failure remains. aZ2service manual download site
 aZ2service manual download site
 aZ2service manual download site
Measuring IC803 output only 3 v, (3) feet touch IC803 hot, fault IC803 load circuit are (standby power supply principle see chart). From the schematic diagram, the output IC803 (3) + 5 V is the main power standby circuit, press the power switch on the front panel, standby power supply and the output voltage of 8.5 V after IC803 voltage stabilizer for IC1205, IC1206, IC1211, ICI212, IC1213 and power light circuit provide stable working voltage + 5 V. For this load short circuit and load for integrated circuit fault, measuring the road resistance is very difficult to make accurate judgment; Long-term practice proves that the use of cutting load of all stripes one by one, to cut off the power supply is one of the most effective method. When cut off IC1213 (22) (61), and (37) (38), connected to the + 5 v, output IC803 + 5 v voltage return to normal. Proved that the author of the original concern: the microprocessor indirect damage of short circuit. The machine model for MN1871611TAK microprocessor, a new microprocessor, troubleshooting.aZ2service manual download site