Touch screens are frequently used electronic products, and it is inevitable that problems will arise. I believe that many people use touch screens and touch screens cannot be used due to malfunctions. So how to repair these common faults of the touch screen? This article describes the methods of solving and maintaining some common faults according to the type of touch screen for reference.

First, surface acoustic wave touch screen

(1) Fault One: Touch Offset

Phenomenon 1: The position touched by the finger does not coincide with the mouse arrow.

Cause 1: After the driver is installed, the center of the bull’s-eye is not vertically touched when correcting the position.

Solution 1: Recalibrate the position.

Phenomenon 2: The touch in some areas is accurate and the touch in some areas is biased.

Cause 2: The sound wave reflection fringes on the periphery of the surface acoustic wave touch screen accumulate a large amount of dust or scale, which affects the transmission of the sound wave signal.

Solution 2: Clean the touch screen. Pay special attention to clean the sound reflection stripes on the four sides of the touch screen. When cleaning, disconnect the power supply of the touch screen control card.

(2) Fault 2: Touch no response

Phenomenon: The mouse arrow does not move when the screen is touched, and no position change has occurred.

Cause: There are many reasons for this phenomenon, which are explained one by one below:

1 The sound wave reflection fringes on the four periphery of the surface acoustic wave touch screen have very serious accumulation of dust or scale, resulting in failure of the touch screen;

2 The touch screen has failed;

3 The touch screen control card has failed;

4 The touch screen signal line has failed;

5 The host computer’s serial port has failed;

6 Computer’s operating system has failed;

7 Touch screen driver installation error.

Solution:

1 Observe the touch screen signal indicator. The lamp blinks regularly under normal conditions and flashes approximately once per second. When the screen is touched, the indicator light is always on. After the touch is stopped, the indicator lamp flashes.

2 If the signal light is still on without touching it, first check if the touch screen needs to be cleaned; secondly, check whether the serial port number connected to the hardware matches the serial port number set by the software, and whether the serial port of the host computer is working properly.

3 Run the COMDUMP command on the driver disk. The command is the DOS command. After the COMDUMP command, add a space and the serial port code 1 or 2 and touch the screen to see if there is data rolling out. If the data is rolled out, the hardware connection is normal. Check whether the software settings are correct and whether there is a conflict with other hardware devices. If there is no data rolling out, the hardware fails and the specific point of failure is to be determined.

4 Run the SAWDUMP command in the driver disk. The command is the DOS command. When the program is running, the program will ask for the type of control card, the port number of the connection, and the transfer rate. Then the program will read the relevant data from the control card. Please pay attention to the AGC value of the X-axis AGC and Y-axis in the lower left corner of the screen. If the value of any axis is 255, the transducer of this axis is faulty and needs to be repaired.

5 After installing the driver for the first time, pay attention to the details of the system error. “No control card found”, “No touch screen is connected”, etc. Check the corresponding parts as prompted. For example, if the touch screen signal line is connected with the control card firmly, whether the keyboard takes the wire is connected with the host.

6 If you still can not rule out, please professional service.

Two, five-wire resistive touch screen

(1) Fault One: Touch Offset

Phenomenon 1: The position touched by the finger does not coincide with the mouse arrow.

Cause 1: After installing the driver, the center of the bull’s-eye is not vertically touched when correcting the position.

2 The signal line on the touch screen is in poor contact or open circuit.

Solution 1: Recalibrate the location; find a breakpoint, reconnect, or replace the touchscreen.

Phenomenon 2: When not touching, the mouse arrow always stays at a certain position; when touched, the mouse pointer is at the midpoint between the touch point and the original stop point.

Cause 2: There is foreign matter (non-active touch) pressing the effective working area of ​​the five-wire resistive touch screen.

Solution 2: Remove the foreign matter in the effective work area of ​​the pressed five-wire resistive touch screen.

(2) Fault 2: Touch no response

Phenomenon: The mouse arrow does not move when the screen is touched, and no position change has occurred.

Cause: There are many reasons for this phenomenon, which are explained one by one below:

1 The touch screen has failed;

2 Touch screen control card has failed;

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