This machine circuit characteristic for: (1) the switch power supply line for self-excited synchronous serial output circuit, and is equipped with a perfect over voltage, over current protection circuit, is mainly composed of elements such as Q902 silicon controlled; (2) remote control the power on/off control circuit, the microprocessor M50432-551 - sp (30) foot (side) power on/off control and drive circuit Q904, etc. The control mode with cut line oscillation circuit power mode. Boot, IC1101 foot (30) output low level (OV) - > Q904 conduction - around 10 v line start voltage - supply IC501 (24) feet, make the line scan the oscillation circuit initial work; When shutdown is on the contrary (see chart). Cncservice manual download site
 Cncservice manual download site
 Cncservice manual download site
Maintenance methods: Cncservice manual download site
 Cncservice manual download site
(1) through the voltage test points first, for example: the thyristor protection circuit Q902 control pole, IC1101 foot (30) remote control the main power on/off control end, IC501 (24) foot (line to start the power supply side) of the key points such as voltage method, to find the abnormal spot, and narrowing the scope of the fault. The results did not find the action of thyristor protection circuit. But found IC1101 (30) feet, IC501 abnormal power supply voltage (24) feet; (2) through a wire short electronic switch Q904c, e or diode to IC1101 short (30 feet) method, that is to judge the fault in the motherboard and CPU circuit board of remote control system. After short sub, the motherboard does not fail, it seems that the fault is a remote control system CPU circuit boards: Cncservice manual download site
 Cncservice manual download site
(3) by detecting the microprocessor IC1101 pin voltage, especially to (42) foot (VDD = 5 v), (16) foot (reset) and (33) (34) the feet (4 MHZ clock) CPU work three necessary conditions such as voltage (or waveform) detection, further judge fault occurred in the external circuit, the microprocessor itself. Because at the moment it is difficult to accurately judge the fault parts, therefore according to the "easy first then difficult", "first" after the maintenance principle, to replace the 4 MHZ crystal vibration of commissioning. No fault has been made since then, for a day or two, but after a few days, and repeat the above problems.

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