Human-machine interface (touch screen) repair case

As long as the factory is more or less will use the touch screen, touch screen failure is more, the touch screen repair has become a factory problem, no way to operate can not work, today I touch screen repair case here for everyone ,for reference.
First, the Siemens touch screen repair TP270
Symptoms: power DC24V, the screen matte, the current is about 230mA
Repair process: touch the screen by hand, the buzzer has a response, indicating that the program is operating normally. The amount of high voltage bar 12VDC voltage is normal, the control voltage ENABLE low for the normal low. Description Fault occurs in high voltage circuit or lamp has been damaged. Disassembled found a black tube has been replaced after the lamp is still dark, check the high voltage transformer has also been damaged. No such high-voltage transformer on the market, so buy a LCD with two high-voltage bar, then fixed line, power is normal, troubleshooting
Second, Hitech touch screen repair PWS500
Symptom: After power on the screen no display, the current is about 100mA
Repair process: Touch the screen, the buzzer is not responding, indicating that the program is not running properly. Multimeter measurement of several groups of voltage 3.3V, 5.1V, 12V are normal. According to the user’s feedback, after the user found that the touch screen failed, he tried to repair it. During the power-on process, a normal situation occurred. However, it was not alright after the power was cut off. Analysis of a pin virtual solder joints, making the bus error, so the program can not run. Then use the hot air gun to heat the leg of the close-legged chip while pressing the chip with the tweezers to re-fuse the leg and the tin. After the above treatment, reboot, the current rose to 470mA, everything is normal.
Third, no reaction after touch failure
In some applications, due to poor grounding performance, the control box housing is covered with a large amount of static electricity, which may affect the working electric field inside the control box and cause the touch to gradually fail. At this point, use a wire to ground the control box enclosure and restart.
Fourth, the touch screen is unstable
Touch a system touch screen, its work is very unstable, and sometimes can click normal, and sometimes no response.
In response to this phenomenon, should focus on checking the wiring interface is loose, serial and interrupt number is there any conflict.
Fifth, no response touch screen failure
First check the wiring interface is loose, and then check the serial port and interrupt number whether there is a conflict, if there are conflicts, resources should be adjusted to avoid conflicts. Then check the touch screen surface cracks, if cracks should be promptly replaced. Also need to check the touch screen surface dirt, if so, with a soft cloth to remove. Observe whether the indicator light on the control box is working normally. When normal, the indicator light is green and blinks.
Six, Fujitsu touch screen repair 650
Suitable models: 660,670,253,280,1120,2610,2620,2630
Symptoms: touch screen handwriting is invalid, the keyboard is normal, pointing stick mouse failure, an external USB mouse can be used normally
Repair process: According to the previous maintenance experience, you can determine the touch lens is no problem, is pointing rod damage. After the replacement of the pointing stick to the above problems can be solved immediately, because the pointing stick easily damaged. Most series of Fujitsu touch screen encounter the above problems, you can change the pointing stick to fix the fault.