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Many people encounter situations where the touchscreen cannot be used due to faults while using it. This is mainly because the touchscreen is a relatively precise device, and due to its nature of being open to the public, its usage frequency is high, and the quality of users varies, resulting in frequent faults. Below, we will introduce some common faults of touchscreens and their solutions and maintenance methods:
When a touchscreen fails, the first step is to check whether the control card power supply is normal, whether the Windows driver is installed correctly, and then check whether the touchscreen calibration in Windows is completed. You should also check whether the serial port is functioning properly and whether the serial cable is connected correctly.
Below are some examples to illustrate the diagnostic methods for touchscreen faults.
1. Touchscreen Inaccuracy
Fault Phenomenon:A surface acoustic wave touchscreen cannot complete the corresponding operation when touched at a specific point on the display screen.
Fault Analysis and Handling
This phenomenon may occur because dust covers the reflective stripes around the touchscreen after a period of use. You can wipe it with a dry soft cloth, then power off, restart the computer, and recalibrate. It is also possible that the reflective stripes of the acoustic screen are slightly damaged; in this case, it cannot be fully repaired.
If it is a capacitive touchscreen, the screen calibration program can be run under the following conditions: (Start — Program — Microtouch Touchware)
1) After the driver software is installed for the first time.
2) After every change in the monitor’s resolution or display mode.
3) After every change in the displayed area.
4) After every adjustment of the controller’s frequency.
5) Whenever the cursor does not correspond to the touch point.
After calibration, the calibration data is stored in the controller’s registers, so there is no need to recalibrate the screen after each system startup.
2. Touchscreen Unresponsive
Fault Phenomenon:A touchscreen does not work and does not respond when any part is touched.
Fault Analysis and Handling
First, check if any connection interfaces are loose, then check for conflicts in the serial port and interrupt numbers. If there are conflicts, adjust the resources to avoid them. Check if there are cracks on the surface of the touchscreen; if there are, replace it in time. Also, check if there is dirt on the touchscreen surface; if so, clean it with a soft cloth. Observe whether the indicator light on the control box is functioning normally; normally, the indicator light should be green and blinking.
If all the above parts are normal, you can check the touchscreen using the replacement method, first replacing the control box, then the touchscreen, and finally the main unit.
If it is a surface acoustic wave touchscreen, the following repairs can be made:
1. It is possible that one of the connections in the touchscreen wiring, which connects to the main unit’s keyboard port (taking 5 volts for touchscreen operating voltage), is not connected; please check the wiring.
2. It is possible that the serial port number selected during the installation of the touchscreen driver does not correspond to the actual serial port number connected to the touchscreen; please uninstall the driver and reinstall it.
3. It is possible that the main unit is a domestic original machine, and the installed operating system is an OEM version that has been adjusted by the manufacturer, causing non-standard serial communication that is incompatible with the touchscreen driver. If feasible, please format the hard disk and install the system after installing the touchscreen driver.
4. It is possible that the version of the touchscreen driver is too low; please install the latest driver.
5. Check if there are any devices in the main unit that conflict with the serial port resources; check all hardware devices and adjust them. For example, some network cards default to IRQ 3 after installation, conflicting with IRQ for COM2; in this case, change the IRQ of the network card to an unused IRQ.
If it is a resistive touchscreen, the following repairs can be made:
1. Check whether the touchscreen wiring is connected correctly; one of the connections to the main unit’s keyboard port (taking 5 volts for touchscreen operating voltage) should be checked.
2. Observe the status of the control box light; if it does not light up or shows a red light, it indicates that the control box is faulty and needs replacement.
3. If none of the above conditions are confirmed, please delete the touchscreen driver, restart the computer, and reinstall the driver, or replace it with a newer version of the driver.
4. Check if there are devices in the main unit that conflict with the serial port resources; check all hardware devices and adjust them. For example, some network cards default to IRQ 3 after installation, conflicting with IRQ for COM2; in this case, change the IRQ of the network card to an unused IRQ. It may also be that the computer motherboard is incompatible with the touchscreen control box; please replace the main unit or motherboard.
5. If the touchscreen cannot be touched in certain areas after being used for a long time (3-4 years), the touchscreen may be faulty and should be replaced.
If it is a capacitive touchscreen, the following repairs can be made:
1) Check whether the touchscreen wiring is connected correctly. If it is an external box control card, the control box part connects directly with the cable extending from the touchscreen. The power part connects through a keyboard conversion head (the small rubber head next to the RS232 port connector must be pulled out before the power line can be inserted), one end connects to the main unit’s keyboard port, and the other end connects to the computer keyboard. One small end of the 5V power supply should be inserted into the connection of the RS232 port, and the RS232 connector extending from the control box should be plugged into the main unit’s 9-pin hole. If your main unit can use a 25-pin hole, please purchase a 9-25 adapter for conversion. If your main unit’s keyboard port is the original small keyboard port, please purchase a pair of adapters from large keyboard to small keyboard.
2) If it is a built-in card type, check whether the jumpers are set correctly according to the control card’s jumper instructions. Due to different configurations of user machines and peripherals, to avoid conflicts between the touchscreen and user peripherals, MicroTouch provides jumper instructions for the control card for customers to choose. Control card address jumper setting instructions:
COM Port Settings
CommPortI/OA1A2A3A4A5A6
COM13F8-3FFONOFFONOFFONOFF
COM22F8-2FFOFFONONOFFONOFF
COM33E8-3EFONOFFOFFONONOFF
COM42E8-2EFOFFONOFFONONOFF
COM52E0-3E8OFFONOFFONOFFON
COM62F0-2F8OFFONONOFFOFFON
COM73E0-3E8ONOFFOFFONOFFON
COM83F0-3F8ONOFFONOFFOFFON
The combination of COM port and interrupt jumpers should be set as follows. Special cases are exceptions.
COM1->IRQ4|COM2->IRQ3|COM3->IRQ4|COM4->IRQ3
3. Long Touchscreen Response Time
Fault Phenomenon:A touchscreen requires a long time to respond after being touched.
Fault Analysis and Handling
This may be due to droplets of water sticking to the touchscreen. Simply wipe it with a dry soft cloth. It may also be that the main unit is of low quality, such as having a low clock frequency; in this case, it is best to replace the main unit.
4. Localized Touchscreen Unresponsiveness
Fault Phenomenon:A touchscreen does not respond in certain areas when touched.
Fault Analysis and Handling
This may occur because the reflective stripes of the touchscreen are covered in certain areas; you can wipe it clean with a dry soft cloth. It may also be due to the reflective stripes being scratched by hard objects, which cannot be repaired.
5. Touchscreen Normal but Computer Inoperable
Fault Phenomenon:A touchscreen is functioning normally, but the computer cannot be operated when connected to the main unit.
Fault Analysis and Handling
This may be because the touchscreen control card receives the operating signal before the main unit loads the touchscreen driver. Simply power off and then restart the computer. It may also be that the touchscreen driver version is too low and needs to be updated to the latest version.
6. No Response After First Startup of Touchscreen After Driver Installation
Fault Phenomenon:A touchscreen does not respond after being started for the first time after driver installation.
Fault Analysis and Handling
First, confirm whether the touchscreen wiring is connected correctly. If not, power off and correctly connect all wires. Then check if there are devices in the main unit that conflict with the serial port resources; check all hardware devices and adjust them. For example, some network cards default to IRQ 3 after installation, conflicting with IRQ for COM2; in this case, change the IRQ of the network card to an unused IRQ.
7. No Response After Using for Some Time
Fault Phenomenon:A touchscreen does not respond after being used for a period of time after startup.
Fault Analysis and Handling
1. Check whether the “Monitor Energy Saving Settings” in Windows 9x is set to turn off the hard disk. The method is to right-click on the desktop, select the “Properties” command, then select the “Screen Saver” tab from the dialog box, click the “Settings” button, and set the parameters to “Always On” for the power scheme, while the rest should be set to “Never”.
2. In some cases, due to poor grounding, a large amount of static electricity accumulates on the control box shell, affecting the working electric field inside the control box and causing the touch to gradually fail. At this time, grounding the control box shell with a wire and restarting it can resolve the issue.
3. Surface acoustic wave touchscreens, when working, have sound waves all over the touchscreen surface. If the touchscreen is not wiped for a long time, excessive dust accumulation may block the reflective stripes, preventing the touchscreen from functioning normally. For touchscreen displays, gently wipe the dust on the reflective stripes around the screen using a clean business card or banknote through the gap between the display cover and the touchscreen, then restart the computer. For all-in-one touch machines, you can open the front cover of the display and use a clean towel to wipe the dust from the reflective stripes around it, then restart the computer.
4. Many all-in-one touchscreen control boxes take power from the all-in-one machine rather than from the main unit. Therefore, you should also check whether the 5V output from the all-in-one machine’s power supply is correct. Sometimes, if the instantaneous current is too high, the fuse may blow, in which case the fuse needs to be replaced.
8. Touchscreen Click Accuracy Decreases
Fault Phenomenon:A touchscreen’s click accuracy decreases, making it difficult to position the cursor.
Fault Analysis and Handling
1. Run the touchscreen calibration program. (Start — Settings — Control Panel — Acoustic Screen — Calibrate Button).
2. If it is a newly purchased touchscreen, try deleting the driver, then power off the main unit for 5 seconds and power it back on to reinstall the driver.
3. If the above methods do not work, it may be that the reflective stripes of the acoustic screen were slightly damaged during transportation and cannot be fully repaired. You can calibrate by offsetting the calibration target in the opposite direction (relative to the direction away from the mouse).
4. If the acoustic screen becomes inaccurate after a period of use, it may be because the reflective stripes or transducers around the screen are covered in dust. If you are using our company’s KA-type cabinet, you can open the top cover and clean its surface with a dry soft cloth soaked in industrial alcohol or glass cleaner, then restart the system. Be careful not to damage the transducers at the left top, right top, and right bottom. Then power off and restart the computer and recalibrate.
5. If there are droplets of water or other soft substances stuck to the surface of the touchscreen, they may cause the touchscreen to misinterpret touches, making it inaccurate; simply remove them.
Touchscreen Unable to CalibrateFault Analysis and Handling
1. If you are using a Lenovo main unit, the pre-installed MOUSEWARE software conflicts with the touchscreen driver. Please delete this software and restart to run the calibration program.
2. It is possible that the touchscreen control card received an operating signal before the main unit loads the touchscreen driver. Please power off, restart the computer, and recalibrate.
3. The touchscreen driver installation may have been abnormal; please delete the driver and reinstall it. (Delete it from the control panel’s add/remove programs).
4. It is possible that after a period of use, the reflective stripes around the acoustic screen are covered in a large amount of dust, preventing calibration. If you are using our company’s KA-type cabinet, you can open the top cover and wipe the dust with a dry soft cloth, being careful not to damage the transducers at the left top, right top, and right bottom. Then start the computer and calibrate.
9. Mouse Stays at a Point on the Touchscreen
Fault Analysis and Handling
This situation occurs because the touch area of the resistive screen (the surface of the resistive screen is divided into touch and non-touch areas; clicking on the non-touch area has no response) is pressed by the display shell or cabinet shell, equivalent to being touched at a certain point continuously. If the cabinet shell presses the touch area, you can increase the distance between the cabinet and the display screen. If the display shell presses the touch area, you can try loosening the screws of the display shell a bit to see if it helps.
10. Touchscreen Works Unstable
Fault Phenomenon:A touchscreen works very unstably; sometimes it can click normally, and sometimes it does not respond.
Fault Analysis and Handling
For this phenomenon, focus on checking whether the connection interfaces are loose and whether there are conflicts in the serial port and interrupt numbers.
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Siemens All-Subject + TIA Portal + EPLAN Electrical Drawing Video Recordings for Sale at Low Prices!
Chuangkong Education Siemens All-Subject Class Course Introduction
