The print head of AR3200 printer adopts super-strong design, and its monitoring program also provides the function of printing needle adjustment (similar to the popular "maintenance-free printer needle break" software). However, if you work for a long time, the print head of the printer will still have faults such as broken needle and invalid reset spring. Because the printing needle adjustment function can only compensate no more than two broken needles, and the use of this function will inevitably increase the load of other needles, it is best to repair the printing head as soon as possible when the above faults occur.

First, remove the print head.

AR3200 print head is exquisitely designed, and it does not need to be fixed with screws or bonded with all-purpose adhesive. When disassembling, you don't need to use special tools, just follow the following steps:

1. Remove the black plastic case and gently lift it from the plastic case buckle with a flat-head screwdriver or tweezers.

2. Remove two steel claw buckles;

3. Remove the two metal back covers;

4. Remove the plastic ring and washer used to fix the printing needle.

At this point, the roots of 24 printing needles have been completely exposed.

Second, repair the print head.

1. If all 24 needles are visually intact and the printing effect is similar to that when the needles are broken, first check whether the return spring is invalid. The specific method is to gently press the welding part of 24 stitches with your thumb, and then release it. If the needle tip remains outside the hole and cannot bounce back, the return spring of the needle will fail. The spring can be taken out, slightly elongated, restored to elasticity, or replaced.

2. If all pins and springs are in good condition, use a multimeter to check whether the print drive coil is burnt out. The wire diameter of the coil is so thin that it is difficult for users to wind it themselves. If it burns out, it must be replaced.

3. If there are few broken needles, first check whether the broken needles are still in the print head. If it is confirmed that the broken head has been taken out, a new needle will do.

4. If there are a large number of broken needles, or the broken needles are left in the print head, it is not easy to take them out. Then, take out all the printing pins, thoroughly clean the two plastic pins and the four plastic pins with alcohol, and blow dry them with a hair dryer. Be careful not to lose the plastic washer and spring when taking the needle. In order to make the load of each spring as uniform as possible, it is best to exchange the positions of 24 return springs. The four plastic guide pins are numbered 1, 2, 3 and 4 respectively from bottom to top, and the number of grooves on the guide pins is the same as that of the guide pins, so it is not allowed to be misplaced during reassembly. After taking out all the broken needles and replacing them with new ones, you can thread again. Threading a needle is a very meticulous job. It's best not to thread the needle. 1, 12, 13, 24 (located on the upper and lower sides of the print head) first, because the positions of these needles are easy to confirm, and it is clear at a glance whether they are wrongly installed. After all the 24 pins are installed, install the print head in the reverse order of disassembly, and the maintenance is completed.

Solving the problem that the printer can't work normally under Chinese Windows 95 by "replacement method"

Chinese Windows 95 comes with many printer drivers, and all common printers have drivers. Due to the long use time, the original installation disk was accidentally damaged or lost, and there is no driver that can be directly used in Chinese Windows95. Therefore, for this kind of printer, if you want to use it conveniently in Chinese Windows 95, you need to equip it with appropriate drivers. The following two methods can solve this kind of problem.

First, the font replacement method

This method is suitable for printers with Chinese Windows3.2 drivers installed. Open the control panel in Windows95, double-click the Printers folder, and then double-click Add Printer to add the printer directly to Windows 95 using the original printer driver disk. However, due to Windows95' s expansion and update of the font library of Songti and Bold, when the printer installed in this way edits the manuscript with software such as WORD, Songti and Bold (other fonts are not) often overlap seriously and become unrecognizable. If you increase the character spacing in the font dialog box, although the display problem can be solved, the character spacing will be too large when printing. At this time, as long as the font files (simhei.ttf, simsun.ttf) that this printer can normally display and print in Windows3.2 are copied to the FONTS subdirectory in Windows95 to cover the original font files in Windows95, the original manuscript can be edited, typeset and printed normally (Note: this method may lead to the decline of the font display quality displayed on the screen of Windows95, which is manifested by the loss of strokes of some Chinese characters. If you don't often use Song typeface, you can consider keeping the original Song typeface library of Chinese Windows95.

Second, the drive substitution method

Some popular printers (such as HP laser printer and Epson stylus printer) can be simulated by programming. Usually, we can get the information whether the printer can simulate other printers from the instructions and driver description files attached to the printer. If it can be simulated, then we only need to set up the printer's DPI switch and other components according to the requirements of the manual, turn on its simulation mode, and then install the corresponding driver.

If the printer does not have emulation function, we can consider using a similar printer driver. Generally speaking, the drive structure of the same series of printers produced by the same manufacturer is similar, and the substitution effect is better. For example, the HP4LC laser printer is driven by HP5L under Chinese Windows, and the effect of printing files is very ideal. However, some later printer drivers can't support the previous version well. At this time, we can consider replacing it with the most widely used printer drivers, such as Epson LQ- 1600K series drivers for needle printers, HP P series and L series drivers for laser printers, and inkjet printers are more complicated, so it is better to find its replacement drivers according to the original manufacturers.

If all the above methods fail, you can use the printer driver marked "GENERIC/TEXT" provided by Windows 95. This printer driver is considered to be running in an unsatisfactory working environment, but according to the test, it has a good effect of printing manuscripts and can be used as a temporary emergency.

An example of solving the fault of driving circuit of AR3240 printer

An AR3240 printer, after turning on the power, the carriage stopped at the same place and could not return to its original position, and all the buttons on the panel failed. After the flameout, the carriage moves normally. Because the Chinese character car can't return to its original position when it is powered on, the hand-pushing Chinese character car moves normally after it is powered off, obviously the possibility of the Chinese character car getting stuck can be ruled out. The font frame of AR3240 printer is driven by stepping motor through belt and other transmission devices. In order to reduce the locking current, the stepper motor adopts high and low voltage driving modes respectively. When the motor does not rotate, TR2 is turned off, and the motor coil is powered by Vl(3.8V) low voltage; When the motor is about to rotate, TR2 is turned on, and the motor is powered by Vm(37V) at high voltage (TR5~TR7 are switch tubes for controlling the turn-on of the motor coil). Open the cover and find that the fuse tube F(3.5A), transistor TR202(D 1593), TR2(B825) and TR7(D 1725) are damaged, and nothing else is abnormal. Because it is difficult to buy the original transistor in the market, I checked the transistor specifications, chose TIP42C instead of B825, and chose 1 1A instead of D 1725, and MJE 13005 instead of D 1593, and then turned on the power. Everything is all right, and we are troubleshooting. The printer can't print normally under Windows 95.

A compatible computer equipped with Pentium 133 CPU, 8M memory and 1.2G hard disk is installed with Windows 95 OSR2 operating system and connected to an Epson LQ-1600k Ⅱ printer. Under Windows 95, the printer works abnormally, and the test page is printed with paper or some abnormal characters.

There may be many reasons. Virus infection, damaged or mismatched printer driver, improper parallel port and printer settings, interface cable and host printer card problems, and printer itself problems will all cause the printer to fail to work normally.

1. First, return to DOS and use the Print Screen function. The printer is working normally. Explain that there is no hardware fault in the printer, and there is no problem with the print interface line and the host print card.

2. The hard disk was tested with KV300, and no virus was found, so it was confirmed that the hard disk was not infected.

3. I suspect that the printer driver is not installed correctly, so I start Windows 95, enter the desktop "My Computer" window, open the "Printers" folder, double-click the "Add Printer" icon, then reinstall the printer from the installation disk according to the prompt of the "Printer Installation Wizard", and select "Epson LQ- 1600k" in the "Printer List".

4. Because the installation CD is not used for a long time, the possibility of printer driver damage is ruled out.

5. Check the system equipment carefully, and there is no "resource conflict".

6. Check the background printing settings, and change the EMF data format of background printing to RAW data format, and the printer fault still exists; Select "Direct Output to Printer" to turn off the background printing function, and the printer fault still exists. Determine that the fault has nothing to do with background printing settings.

7. Look carefully at the "Details" tab in the printer properties, and you can see that

Print to the following ports:

LPT 1: (ECP printer port)

So I think the fault may be related to the parallel port setting in CMOS.

Restart to enter CMOS, open the menu of integrated peripherals, and find the parallel port settings as follows:

On-board parallel port: 378/IRQ7 (working setting of parallel port on motherboard)

On-board parallel mode: ECP (parallel port working mode on motherboard)

Ecpmode uses DMA:1(DMA number used in ECP mode).

The onboard parallel port: is set correctly. Select Airborne Parallel Mode:.

ECP (Extended Function Port Extended Parallel Port)

Enhanced parallel port

ECP/EPP (Extended/Enhanced Parallel Port)

Standard parallel port

There are four types, among which the DMA numbers used in ECP and ECP/EPP modes are "1" and "3".

Change the "onboard parallel mode:" setting to SPP (standard mode) (Note: some printers do not support ECP and EPP modes! ), save and exit, restart to enter Windows 95, and select "Print Test Page", OK! The test page printed correctly.

Maintenance of Common Faults of Printer (Motherboard)

Example 1:

Fault phenomenon: after the printer LQ-1600 K Ⅱ is turned on, the font car is reset, and then the indicator light on the control panel is fully turned on and flashes 5 times.

Maintenance method: CPU TMP96C04 1F and TL43 1 are damaged. After replacement, measure whether R6 is 47 ohms. If not, replace R6. When the machine is turned on again, the printer will resume normal operation.

Example 2:

Fault phenomenon: pen leakage during printing.

Maintenance method: firstly, after troubleshooting the print head and head line, if there is still a pen missing, that is, the needle drive tube STA475A is damaged. Each STA475A drives four printing needles, and the damaged STA475A is measured with a multimeter to find out the reason, replace and troubleshoot. If STA475A is damaged, the corresponding coil of the print head cannot be retained and should be replaced. Maintenance of common faults of LQ-1600k Ⅲ printer (motherboard)

Fault phenomenon: The common fault of LQ- 1600kⅲ printer is the damage of parallel port, and the proportion is very large. The damage of parallel port will lead to many abnormal phenomena as follows. If you can check yourself, you can't connect to the computer. Some can't self-check. Some cannot be reset. Power-on reset, no self-check and no online. There is a control panel indicator that flashes and then goes out completely.

There are many other failures. ...

Maintenance method 1: Check whether the +5V voltage is short-circuited to the ground with a multimeter. If it is short-circuited, the interface chips IC-9 and 74LS06 are damaged. Remove 74LS06 first, and then check whether the voltage of +5V is short-circuited to ground. If it is short-circuited, IC-2 will also be damaged. Remove IC-2 and E05B24YA, then measure +5V voltage and replace IC. When the machine is turned on again, the printer will resume normal operation.

Maintenance method 2: use multimeter to check that there is no short circuit between +5V voltage and ground, and then check IC-2 and E05B24YA. If there is any short circuit between the first pin of the chip and 37-54 pins, IC-2 is damaged. In this case, IC-9 will generally be damaged, so it is necessary to replace IC-2 and IC-9 at the same time. Check the surrounding resistance again, and replace it if it is damaged. When the machine is turned on again, the printer will resume normal operation.

Precautions for mainboard maintenance (especially LQ-1600 K Ⅲ): Never remove the copper and platinum of the circuit board when removing the chip. As long as you don't disassemble the circuit board, if you can't repair it well, others can help you repair it, otherwise it will cause new fault points and lead to the scrapping of the motherboard. When loading the chip, be sure to pay attention to the chip pins and pads not to be misaligned or welded, and not to be short-circuited between the chip pins.

Fault phenomenon: pen leakage during printing.

Maintenance method: first use the needle measuring program to detect which needle is missing, and then find which needle to drive the tube after troubleshooting the print head and head line. The main board is marked with the number of the needle drive tube, which corresponds to the needle number of the needle measuring program and is very convenient to find.

An example of fault maintenance of CR3240 printer

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Fault phenomenon: a CR3240 printer can only print one or two pages when printing output with WPS or CCED, sometimes even less than half a page. At the end of a paragraph, when there is a line break or a normal line break, the print head can't start printing from the normal position on the left, but prints after a certain distance, which leads to the printing error of the following characters.

Fault maintenance: I began to suspect that there was a problem with WPS or CCED, and the fault remained after reinstallation. Using the latest antivirus software of KV300(B) and KILL78, no signs of virus damage were found. After replacing the microcomputer and printing line, the problem still cannot be solved, which shows that the fault is not caused by the hardware and software of the microcomputer, but by the printer itself. Open the front cover of the printer and observe the printing process carefully. When the wire feed is abnormal, the carriage (including the print head, ribbon box and other parts) stops instantly, and the drive belt seems to slip. Further inspection shows that the surface of the guide shaft of the print head is dry, oil-free and dusty, and the surface of the guide shaft behind the printing carriage (below the back of the ribbon box) is seriously worn, rusted and rough. It is very difficult to push the print head by hand after the printer is turned off. The preliminary judgment is that the increase of friction resistance between two shafts leads to the increase of transmission resistance, which leads to the transmission belt slipping (or stepping motor out of step) during line changing, and the print head cannot return correctly. First, remove the dust and rust on the two guide shafts, and then add appropriate sewing machine oil to the two shafts several times. The resistance gradually decreases and the self-inspection is normal. After connecting with the microcomputer, try to print a long article, and the printer will resume normal line feed and troubleshooting. I used this method to deal with the abnormal disconnection of two CR3240 printers successively, and both were successful.

Summary: The printer with heavy printing load (high frequency of use) should pay special attention to maintenance, especially the relevant transmission parts should pay attention to timely dust removal and lubricating oil addition, so as to avoid abnormal wire feeding or even burning out the stepping motor due to increased friction resistance and excessive transmission load.

Fault symptoms: CR3240 printer, turn on the power switch, move the carriage to the right about 3CM, and there is no action. At this time, the power indicator light is on and the online light is off. Shut down and restart, the print head carriage moves about 3CM to the right, and then there is no action. After repeated several times, the print head will collide with the right wall, making a "buzzing" sound and unable to move.

Fault maintenance: Because the print head can't return to the initial position all the time, it is estimated that the fault lies in three circuits directly related to the carriage motor reset: carriage initial position detection circuit, carriage motor drive circuit and reset circuit. Because the author is not familiar with the internal circuit of CR3240 printer, I want to compare the plugging and unplugging of two identical printers in my hand and troubleshoot them.

Disassemble the trouble-free printer and find that each control part is connected with the main control board through several sockets on the main control board. Pull them out one by one and start the test. It is found that when CN5 is unplugged, the same fault phenomenon as the fault printer appears. Therefore, it is judged that the fault lies in the circuit connected with CN5. Through circuit tracing, it is found that there are circuits such as paper detection and font initial position detection connected with CN5. According to the fault phenomenon, it is estimated that the fault is likely to be detected in the initial position of the word car. Comparing the optocoupler assembly of two machines to detect the initial position of the preceding vehicle, it is found that the two slits above the optocoupler assembly on the faulty machine are stuck with thick ink, and the detection function is lost. Remove the optical coupler, clean it with anhydrous alcohol, and then reinstall it to eliminate the fault.

Summary: For operators who are inexperienced in maintenance, they can't find the cause of failure directly through instrument testing, but they can still make use of the convenient conditions around them and appropriate methods to carry out simple troubleshooting. As long as you start maintenance, you will gradually accumulate maintenance experience and become a maintenance expert. Keeping the computer room clean and tidy, wiping the parts that may be contaminated in the machine is the best way to reduce and eliminate faults.

Fault phenomenon: During the printing process of a CR3240 printer, the buzzer sounds an alarm and stops printing. There are only power indicator lights and font selection indicator lights on the panel. In the future, this kind of fault phenomenon will appear every time the car is turned on and moved to the right for a certain distance.

Fault maintenance: When using the trolley compartment, it was found that it was free to move, which ruled out the possibility of the compartment being stuck. Measure the high voltage of the power board ++35V, and the output is normal. Check the print head cable and mechanical parts, and no abnormality is found. By replacing the frame part of the printer with another printer that works normally, it is found that the printer still has the above fault phenomenon, while the other printer works normally, so it is judged that the fault occurs in the logic motherboard part of the printer.

Since the printer can't enter the self-test state after each boot, it is estimated that the problem lies in the CPU(TMP90C04 1) and its peripheral circuits. Because of the complex structure of CPU and low failure rate, peripheral circuits are tested first, and IC 1 (M50953BL) pins are tested with oscilloscope. Turn on the power supply, there is obvious negative pulse, and measure the crystal oscillation. It was found that the crystal oscillator began to vibrate at the initial stage of startup, but with the occurrence of the fault, the crystal oscillator stopped vibrating, and the new crystal oscillator was removed, and the fault still existed. It seems that the fault is caused by local damage of CPU, and it will be started only after replacing CPU.

Fault phenomenon: When a CR3240 printer uses friction paper feeding mode, it sometimes enters the self-checking state when it is powered on, and sometimes it enters the self-checking working state when it is reloaded.

Troubleshooting: After the printer control panel is removed and turned on, the printer will still perform self-test, which eliminates the possibility that the SW6 switch is closed due to the depression of the online button on the panel or the SW6 switch is sometimes automatically closed due to poor performance. When measuring TR24(C 1724), it is found that the forward and reverse resistances between its collector and emitter are the same, indicating that TR24 has failed. After replacing TR24, the printer returned to normal operation.

Fault symptom: CR3240 printer will be reset frequently whether it is in standby state or online printing state.

Troubleshooting: According to the working principle of the printer logic motherboard, the printer has two reset modes: power-on reset and in-prime signal reset sent by the host. In addition, a +5V voltage detection reset circuit IC 1(M5 19453BL) is added in the reset circuit, and when the +5V voltage changes, a RES signal is generated to reset the printer. Disconnect the data communication cable between the printer and the computer, and turn on the test power. The fault still exists. Because there is no perfect testing method to determine the quality of IC 1(M5 1953BL), we should monitor the voltage of +5V for a long time. It was found that the voltage of +5V did not change when the printer was reset. The fault is suspected to be caused by IC 1 (M565438).

Fault phenomenon: a CR3240 printer often appears tape hanging phenomenon when printing, and the fault still exists after cleaning the print head and oiling.

Troubleshooting: The elastic force of the return spring of the printing needle is weakened, the needle balance pin moves back and forth due to the wear of the needle holder, and the needle balance pin is worn and broken, which will lead to the failure of the printing needle to receive the needle in time, thus causing the tape hanging phenomenon. Open the print head and check the balance pin of the printing needle. It is found that some of them can move back and forth, obviously because the needle seat in the printing needle is worn. Replace the needle holder in the printing needle and troubleshoot. Fault phenomenon: there is always a thin white line in the printed word, but this white line is much thinner than the white line that appears when the needle is broken.

Troubleshooting: Carefully observe the needle board of the print head, and all 24 needles are not broken. 10 needle is abnormal when using the broken needle maintenance-free software. Check the corresponding print drive coil, and no abnormality is found. Observing with a magnifying glass, it was found that the front end of 10 needle was uneven, and only a part of it touched the printing roller during printing, resulting in a thin white line. Remove the needle, file or replace the needle, and troubleshoot.

Failure phenomenon: the needle is broken during printing, and the printing needle hangs after cleaning the printing head and changing the needle.

Fault maintenance: the needle is still broken after cleaning the print head, indicating that the fault lies in the reset device. Check whether the corresponding inner needle holder and balance pin are worn; Check the return spring and find that the spring is shorter and less elastic than other springs. After replacing the return spring, correct the fault.

Symptoms: The printed characters have thin lines and light colors.

Troubleshooting: Thin lines indicate that the printing needle is in slight contact with the printing roller. Check the needle board of the print head, and the 24 needles are neat and smooth without broken needles. The needle 1 1 is abnormal with the maintenance-free software for broken needles. After checking the inner needle holder and the balance pin, no abnormality was found. Check the corresponding return spring, and find that there is oil stain and dirt between the springs, which can't compress the spring smoothly, and the needle is not in place, resulting in thin lines in the printed words. After cleaning the return spring, correct the fault.