After that, you're the computer maintenance engineer, 12th.

Nineth Chapter port and peripheral faults

An example of a definition

This kind of fault mainly involves serial port, USB port, keyboard, mouse and other equipment fault.

Second, possible phenomenon of failure

1, the keyboard is not working properly, function keys do not work;

2, mouse work is not normal;

3, can not print or under an operating system can not print;

4, external equipment work is not normal;

5, serial communication errors (such as: Transmission data error, lost data, serial device identification, etc.);

6, the use of USB equipment is not normal (such as USB hard drive, can not connect a number of USB devices, etc.);

Iii. parts that may be involved

Components with appropriate ports (such as motherboards), power supplies, connection cables, and settings in the BIOS.

Iv. Points of judgement/order

1, before the maintenance of the preparation

1 Prepare the corresponding port short-circuit ring test fixture;

2 Prepare test program QA, AMI, etc.--these programs require operating in DOS;

3 According to the resources in the station, prepare the corresponding port to use the cable, such as parallel port, printer line, serial line, USB cable and so on.

2. Environmental inspection

1) connection and appearance inspection:

A. The equipment data cable interface is good connection with the host, whether the pin has bent, missing, short connection phenomenon;

B. For some brands of USB hard disk, it should be explained to the user that the best use of external power to make it better work;

C. The connection port and the related control circuit whether has the distortion, discoloration phenomenon;

D. Connect the cable with the device to be connected (for example: two machines connected through a serial port, you should use the null modem cable and can not use the modem line, etc.).

2) Peripheral Inspection:

A. Whether the power adapter of the external device matches the device;

B. Check whether the external device can be powered (including the power supply, and from the host signal port to take electricity);

C. Detect whether it works properly under pure DOS. If not work, should first check the cable or replace peripherals and motherboards;

D. If the external device has a self-test function, you can first check whether it is intact, you can also connect the external equipment to other Lenovo machine detection.