The analysis of the fault of the stylus printer word-Hardware maintenance

Under normal circumstances, the needle-type printer word car mechanism in the left and right displacement should be smooth and stable, so in the printer boot, no matter where the word car in the original position, can return to the initial position of the left, in the printer work when the word car loaded with print head back and forth movement. If the word car failure will make the print head move not in place or not move, resulting in the printing work can not be completed. Below and you specifically discuss the word car fault, the word car fault mainly in the following aspects.
1, the word car mechanism in the dirt too much, often will cause the word car can not be smoothly, at this time can be cleaned to troubleshoot.
2, is the word vehicle mechanism mechanical failure, such as the word car belt wear, the front and rear rail parallelism, and so on, will also make the word car can not be successfully returned to the position, move. This situation can only be replaced by the word wagon belt or word car guide.
3. Motor failure of the word car
The fault of the byte motor itself is mainly a group of stepper motor or multiphase winding coil burnt out (short circuit, open circuit), this fault can be used to directly measure the motor coil winding DC resistance and normal resistance (in general, the motor of the four sets of coils will not all burn out, there is always a group or groups are good) comparison, to judge. If one phase or two phases of the motor coil are burnt out, as long as the coil skeleton is not deformed (rotating shaft with hand, no obvious card astringent can be, at this point in accordance with the motor of the original line diameter and turn number (in the demolition has burned the coil, pay attention to the number of turns, and then use Fileca to measure the diameter) to burn themselves; if the coil skeleton of the motor has been seriously deformed, The new motor should be replaced. In addition, the printer in the long-term use, due to vibration and other reasons, may cause the magnetic steel part of the machine demagnetization, resulting in insufficient motor torque, resulting in the printer in the printing process word car mobile difficult. In this case, the same model of the new motor should be replaced.
4. Switching Circuit failure
For the use of "high voltage drive low voltage lock" motor drive system printer, such as ar-3240,ar-2463,ar-3200,lq-1500,lq-800/1000, and other printers, often high/low voltage switching circuit supply high voltage transistor c~ The case of a breakdown or opening between poles. If the C~e pole breakdown, driving high pressure has been added to the winding of the stepper motor, which may further cause the motor winding burnt out and burned as a driving stepper motor phase signal transistor. If the C~e pole open, high pressure can not supply motor car, motor does not work, the word car will not move.
In addition, there may be a failure in the control signal section of the high/low voltage switch. At this point, it should be based on the specific printer model of the circuit, to be detected and excluded.
5. Vehicle motor lack phase fault
Printer in the electrical work, if the word car stepper motor four-phase winding on a group or two sets of open, it will appear in the original position of the word car jitter or the word car fatigue, and even the word car does not move. This phenomenon may be the word car motor plug contact or disconnection, it is possible that the motor control and driving circuit in the phase control part of the fault. Because of the different kinds of printer's circuit, so the specific circuit for analysis and testing, detect the fault point, to be excluded.
6, stepper motor drive or its peripheral components damaged
Stepper motor drives are some of the printers used to control and drive the word motor of the transistor or dedicated integrated circuit. In the case of AR-3240 and M-2724 printers, the stepper motors are respectively made up of transistor D1579 and D1789 as their respective motor drives, while in dlq-2000k,ar-4400 and CR-3240 printers, they are used as motor drives for word vehicles. , if these devices are damaged, the word car will not work properly. Only the replacement of damaged components can eliminate the fault.
7. The special gate array circuit fault of the motor drive circuit of the word vehicle
The motor drive circuit is controlled by the CPU through a dedicated gate array circuit (such as the E05A09BA in the lq-1600k printer) or an I/O interface circuit (such as AR-3200 in the E05a24ga and XBL-2 printers in the dlq-2000k printer). If this part of the circuit damage will affect the normal operation of the word car, even in the printer when the word car does not return to the initial position.
Although the fault can be attributed to the above five parts, but from the maintenance point of view, the printer should be based on a variety of fault phenomena for specific analysis and diagnosis. The check order is generally: printer word car mechanism (mechanical failure)---motor (each phase coil resistance and torque)---motor drive output outlet resistor value (positive, inverse resistance)---motor drive power supply voltage---drive circuit input, output end of the ground resistance---motor phase control circuit.
The following is an example of three cases of Word vehicle failure analysis and elimination:
1, CR-3240 printer boot after the word car operation is not normal
Symptom: The CR-3240 printer can return to the initial position when the word car starts, and the printer "freezes" when the word car moves to the right in the printing process.
Diagnosis and exclusion: The word car can return to the initial position, indicating that the control logic of the printer is normal, the word motor control signal is also normal, mainly the motor torque is not enough. The reason for the lack of motor torque, in addition to the motor lack of phase operation, there are two reasons: first, the voltage of the driving power is low, the second is the motor itself because of the long-term use of motor because of vibration and other causes of motor magnetic steel parts demagnetization. If the motor drive circuit sla7026m and its peripheral circuit fault possibility are eliminated, the replacement method is used to replace a new word motor after the fault is eliminated.
2, AR-3200 printer boot after the word car operation is not normal
Failure phenomenon: AR-3200 printer After the word car in the original position jitter, with the hand push the word car to move a distance after stopping the alarm.
Diagnosis and exclusion: from the phenomenon of failure analysis, for the word car weakness, generally for the printer's word car mechanism and motor control and drive circuit failure. Check the word vehicle mechanism in the Order of inspection and troubleshoot this part. Then the measurement of the electric motor phase coil resistance, each phase is 5ω, is the normal value. Then use the replacement method to check the torque of the motor (AR-3200 printer's motor used for a period of time after its torque will drop), the results of the torque unchanged, thus excluding the possibility of motor failure of the word car. Measuring the main control circuit board on the motor-driven output plug CN5 of the feet in addition to the positive and reverse resistance, the 2nd foot to the ground short-circuit. Follow the end of the test, check the word motor drive circuit SLA4030 (TA7) phase signal output (9 feet) to the ground short-circuit, which determines SLA4030 damage, after replacement SAL4030, troubleshooting.
3, lq-1900k printer boot after the word car jitter, with a hand push the word car but can move.
Diagnosis and Analysis: from the phenomenon that there are two reasons: first, the mechanical failure of the printer, the second is the word motor and its control and drive circuit has trouble, and for the word motor of a certain phase of the work is not normal. For the mechanical failure of the printer, under normal circumstances, the left and right of the word car should be smooth and stable, so that after the printer to add electricity, no matter where the word car originally stopped, can return to the original position. If the word car mechanism in the dirt too much, or the frame of the shaft wear and tear, so that the word frame sloshing on its axis, will lead to the word car in the process of movement because of the resistance too large and can not smoothly return to the initial position, or return to the initial position is not in place. The solution is to remove the word car mechanism for cleaning, for the shaft wear a serious frame should replace the sleeve. After the above inspection, the initial diagnosis for the motor drive circuit failure. A static measurement of the DC resistance of each phase coil of a word vehicle motor. The measured resistance is about 5 Ω, which indicates that the motor of the word car is normal. The output waveform of each input end (1,8,11,18 foot) of the motor drive circuit sla7024m is observed with oscilloscope, and 8 feet are found without waveform output. Static measurement of 8 feet of positive and reverse resistance, the results are measured positive and reverse resistance values are 1kω, and the normal positive resistance value should be ∞, the reverse resistance value should be 7.5kω, which indicates that sla7024m's 8 feet have been damaged, replacement, troubleshooting.