The special corrective maintenance that Kang Jia T2510 burns switch to be in charge of repeatedly
Breakdown phenomenon: Switch on the mobile phone scamper is safe, burn switch canal. Analysis, switch power source protects circuit to have trouble.
Switch on the mobile phone examination: This machine uses transformation coincidence circuit. And, 5 bend over (pay power source) it is to use switch concussion circuit, circuit is more complex, search to breakdown bring a lot of difficulty, circuit of stabilized voltage control uses 120 bend over one-way silicon controlled rectifier is corrective control, switch canal blasts off extremely the VD905 in circuit of 0.5 ohmic sampling is in charge of for 6.2V stabilized voltage enlarge is in charge of V904 and set to protect sampling, stabilized voltage of experience judgement 6.2V is in charge of paralell connection to attack the possibility that wear to have hardly on 0.5 Europe resistor, can be this canal puncture unluckily, cause stabilized voltage to control out of control, burn down switch is in charge of (2SC4111 high-power is in charge of) . And burn a few repeatedly, it is normal to change 6.2V stabilized voltage to provide the job, this machine rehabilitate. The brief summary after repairing, maintain this machine to cost long, charge loss is big, it is the disaster that VD905 causes, but baffling is, VD905 design blasts off in switch canal extremely, does its main effect protect V904 namely? Still have other objective, but although his puncture protected V904, and did not rise to protect action to circuit, instead smash more important switch valve, with its the design blasts off in switch canal extremely, be in as the design of V904 base class. When the author is being maintained, put this valve in V904 base class. The job is regular. <- - article content- - >