Com 226 comp trouble shooting II theory book
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| 844 Mice And Trackballs FIGURE 25-7 Configuring MouseKeys operation. If no hardware conflict occurs, and cleaning does not correct an intermittent condition, remove the device’s upper housing to expose the PC board, and use your multimeter to check continuity across each wire in the connecting cable. Because you probably will not know which connector pins correspond to which wires at the sensor PC board, place one meter probe on a device’s wire and “ring-out” each connector pin until you find continuity. Make a wiring chart as you go. Each time you find a wire path, wiggle the cable to stimulate any possible intermittent wiring. Repair any intermittent wiring, if possible. If you cannot find continuity or repair faulty wiring, simply replace the pointing device. Symptom 25-2. One or both buttons function erratically (if at all) Buttons are prone to problems from dust accumulation and general contact corrosion. Your first step should be power down your computer and disconnect the pointing device. Remove the ball and upper housing to expose the PC board and switches. Spray a small amount of electronics- grade contact cleaner into each switch, then work each switch to circulate the cleaner. If cleaning does not improve intermittent switch contacts, you might wish to check continuity across the connecting cable. With the ball and housing cover removed, use your multimeter to check continuity across each wire in the connecting cable. Because you probably do not know which connector pins correspond to which wires at the device, place one meter lead on a device wire and “ring-out” each connector pin until you find continuity. Once you find continuity, wiggle the cable to stimulate any possible intermittent wiring. Repair any intermittent wiring if you can, or simply replace the pointing device. Symptom 25-3. The screen cursor appears on the display, but it does not move If the cursor appears, the device driver has loaded correctly and the application program is communicating with the driver. Your first step should be to suspect the serial connection. If there is no serial connection, however, no pulses will modify the cursor’s position. If you find a bad connection, power down your computer before reattaching the device’s serial connector, then restore power and allow the system to reinitialize. If the device is attached correctly to its proper serial port, the problem probably exists in the pointing device’s wiring. Remove the ball and upper housing to expose the PC board, then use your multimeter to check continuity across each wire in the connecting cable. Because you probably do not know which connector pins correspond to which wires in the device, place one meter lead on a device wire and “ring-out” each connector pin until you find continuity. Once you find continuity, wiggle the cable to stimulate any possible intermittent wiring. Repair any intermittent or open wiring if you can, or simply replace the pointing device. Symptom 25-4. The mouse/trackball device driver fails to load The device driver is a short program that allows an application program to access information from a pointing device. Most computer users prefer to load their device drivers during system initialization by invoking the drivers in the CONFIG.SYS or AUTOEXEC.BAT files. Most drivers are written to check for the presence of their respective device first—if the expected device does not respond, the driver will not be loaded into memory. Other drivers load blindly, regardless of whether the expected device is present or not. If the device driver fails to load during initialization, your pointing device might not have been detected. Power down your computer and check the connection of your pointing device. Ensure the device is securely plugged into the proper serial port (or other Download 1.89 Mb. Share with your friends:
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