Laptop Repair thinking method
Under no circumstances must be measured to ensure the normal power supply voltage across the inductor, power failures accounted for laptop repair 40% .
(A): the main power supply ( 10V - 20v ), 1 notebook adapter maximum supply voltage threshold voltage, the two notebook when the battery voltage is low gate threshold voltage. Main supply voltage is not normal boot method. Brownout protection, the protection circuit is isolated problems and battery charge and discharge circuit problem. Power Interface diode ---- ---- ---- insurance field pipe ------ field pipe (the last one is the common point output pole ground resistance at 100 or more, if the resistance is low at 10 a few Ohm even at 0 indicates a common point level circuit after a short circuit. Plug the adapter current 1A above to show before and after the isolation level has short circuit protection circuit
An isolation circuit to short-circuit between the capacitor interface power.
2 isolation protection level after all the high-end venues on the circuit gate capacitance of a short circuit in parallel, to find out the damaged one
3 power chip short circuit.
4 under the possession of a short circuit
5 main north and south bridge chipset shorted
(B) cpu power 0.9v ~~ 1.5v
(C) chipset supply 1.05V , 1.25V , 1.5v , 2.5V , 3.3V , 1.8V , 1.7 , 0.9v
(Four) memory power supply vcc : 2.5V 1.8V 1.5v memory ad when supply VCC one-half
(Five) graphics power 1v1.5v1.17v 1.8v 2.5v 3.3V
. (f) the system power supply 3.3v 5v note that not all machines are produced under the standby measure 3.3v5v ground resistance BGA judge good or bad. Normal resistance at 40 ohm, 3.3V resistance at 10 bit, check the focus of Southbridge, card. 5v resistance is low emphasis Northbridge card, PC card chip. System unit without power output to be measured output filter capacitor is good or bad
Second, the current size of the working relationship, must be under the bare board without a battery
(A) standby current (not all laptops have a standby current) IBM , most machine-made 0.03A to 0.05A Toshiba, Lenovo, Sony, Dell parts of the machine ASUS current 0.01A Sony part of the machine is no standby current is normal, VIA , SIS , AMD is one of the north-south current 0.08A ~~ 0.1A
(B) Current plugged in 0.1A ~~ 0.14A or so, indicating a short circuit board, to measure 3.3v ground resistance judge Southbridge problem, most of the South Bridge card failure. Pc card chip issues
(C) the trigger current at 0.1A ~~ 0.14A issue focuses Southbridge
(Four) trigger current 0.24A ~ ~ 0.3A . Some of the machines power down current is not increased, the focus checkCPU power whether, if not a normal power supply Northbridge check whether two check cpu power supply circuit 3CPU Block Weld 4 Northbridge Weld
(E) the current situation in the absence of memory motherboard 0.3A ~~ 0.45A ~~ 0.5 A once to two times a transition indicate north and south bridge, IO , cpu basic work, plus the memory current 0.5 ~ 0.75 ~ 0.5 hopping memory test showed normal through. But if you check the jump is not normal, then check memory, memory power, Northbridge. Current 0.45 ~ 0.65 ~ 0.75 ~~ 0.9 ~~ 1a hopping basic graphics show through, you can light up the display, if the display is not lit, the focus of the investigation graphics Northbridge
(F) does not add memory plus memory and no significant change in current. BGA test check I / O memory power, plus the graphics memory is checked Northbridge NVIDIA current change in emphasis HP large probability to try the machines graphics problem, screen appears the same picture card failure.
(Vii) the external display, the LCD screen black and white. 1 measured on the screen 3.3V2 screen line 3 graphics 4 screen lg brand appeared shaking screen, black and white, the basic problem is the screen itself
(Eight) Toshiba's part of the machine Huaping BSOD powered down. If NEC large capacitors in CPU replacement seat near six months 330 of the capacitor can be
(Nine) HP machine is three needle interface, power supply connected to the isolation is not working, the power to change the interface dell machine is not charged with a power supply
(J) measuring board display screen line-to-ground resistance of the signal can be judged good or bad graphics
Try plugging maintenance COMS battery, but otherwise it is possible memory
(Xii) netbook current 0.4 current transition does not go up, such as memory, however, do not worry repair Northbridge. First brush bios program, this show mostly bios procedural problems caused.
These are intel chipsets, for example ;
Amd the cpu have large current 0.6 to 0.8 above
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