Hisense HK950 Service Manual page 14

2）human-caused malfunctions: components are damaged due to not complying with the operating rules such as
insert and pull the plug in a working condition etc.
3）hardware malfunctions: problems of manufacturing process or material quality problem；poor contact
between boards and connectors；board solder joint is broken or unstable、the connecting wires break down etc.
4）software malfunctions：it can be divided into the fault caused by the human reason、the fault caused by
system software and the application itself, and the fault caused by virus;
5） impact caused by the environment ： it mainly includes voltage anomaly fluctuation, temperature and humidity,
dust, electromagnetic radiation, electrostatic and other factors ；
4.2 Principle of handling faults
1）From software to hardware：The fault should be analyzed first from the operating system and software，for
example: The partition table is missing、COMS is improperly set up、the virus destroy the system.The error of hard
disk main boot sector or the register file. After eliminating the errors of software, we can start diagnosis the cause of
the failure from the hardware aspect.
2） From the outside to the inside： We should diagnosis the peripheral first ， then turn to the host, fault diagnosis
should be based on the system error；
3）Power supply first：Power supply is the key to whether the machine can work normally, so we should check
the power supply first and then diagnosis the other parts.
4）From general to special：Consider the most likely cause of failure, for example: If the hard disk cannot work
normally, we should check if the power cable and the data line is loose, reconnecting them can solve the problem.5）
From simple to complex： First eliminate some faults that are easy to work out, then eliminate those faults that are not
easy to solve.
4.3 Common methods of eliminating the faults
1）observation
Choose what to observe based on the specific situation，use your eyes、 ears、 nose and other organs to judge the
failure, observe if there is charred、variant、abnormal sound、falling off and other phenomena;
The principles of observation are as follows：
From outside to inside：observe the environment of the outside and inside of the machine；
From simple to complex：look、listen and smell；then have a measurement or test.
2）re-install method
Remove the board which may have a fault，wipe it clean with rubber and then re-insert to make sure it is in a
good contact.
3） replacement method
Replace the defective part with a similar one which have the same functions to find out if the failure is gone.
4）minimum system method
HK950 Service Manual