1. The temperature of the print head and the failure of the detection system: such as the temperature resistance on the head is open, the head cable is disconnected, the print head is not cut, etc.;
Note: The normal voltage of the CPU-73 pin is +0.54V. If the print head is not connected or the corresponding line is disconnected, all the lights will flash immediately after power on.
Netizen speech:< /p>
“I heard that the head cannot be measured!”;”The solder joint is short-circuited after replacing the coil of the print head”;”Boss, the print head cable is inserted backwards”;< /p>
2. The +35V voltage is too high, too low or the detection system is faulty: not available (no example has been seen in the netizens’ speech);
Note: The normal voltage of CPU-74 pin is +3.94V; when the voltage rises to +4.5V, all the lights will flash and the head will not move;
When the drop reaches <=+3.5V, all the lights are on (not flashing), and the head does not move; It may be caused by the voltage being too high (when the voltage rises to +4.4V).
3. “Initial position” of the print head and finding faults: initial position detection The system is broken, the performance of the carriage motor is not good, etc; ;”A line of the print head home position sensor (HOME sensor) is broken”;”It seems that the connector of the carriage motor on the main board is loose”;”It may be that there is a problem with the spindle in the machine”;
4.Vref voltage and detection system (including CPU) failure: ZD1 is bad, CPU is bad, etc.;
Note: The normal voltage of CPU-78 pin is +4.77V:
Netizen speech:
“A 4.77V regulator on the motherboard is broken… .Small red tube”—ZD1—Editor’s note;”I tried the same fault, and it was OK after changing the CPU”;
5. Motherboard The upper part of the line is short-circuited, leaking or open-circuit fault (IC2 chip is the key)….
Netizen speech:
“Some feet of the BIOS are corroded, which is caused by poor contact”;”The motherboard is obviously corroded”;”In short It is the phenomenon that the CPU self-test has passed, and when other ports are further tested, some ports are faulty, so they fail to pass the test. This requires careful inspection of each circuit, focusing on short circuits (—leakage—Editor’s Note), followed by open circuits, mechanical faults are also present but very few, and at the same time follow circuit faults”.