A peer to send a Tongfang Fengrui K401 laptop motherboard repair, said the failure to turn brown, Oh, really convenient, eliminating the need for a teardown time. . . Check this board for the TOPSTAR OEM M42G models, plug in the power, current 0.04A, basically normal. . Try to power on, the current went to 0.10A on the power-down, and then auto-boot, went to 0.10A, the power-down. And then did not respond. . .
Examination revealed that this machine had been repaired countless many have fixed places, it is clear, R554R553 has been dismantled for others to go, and asked colleagues said that this machine had been revised to others before, this aircraft had entered over the water, but has to clean up. . . .
Cha circuit that, the two resistance BIOS chip 8 feet 0 Europe for the resistance of resistor, since R554 is received + V3.3AL, appears to participate in BIOS for this machine is triggered, resistance removed, of course not trigger啦. . After the installation of resistance. The amount of 8-pin BIOS chip has 3.3V power supply, playing a foot 2 feet 5 feet 6 feet have waveforms, indicating BIOS has been working properly. . . . .
Try to start, triggering the normal, but the current is 0.45A went to stay three seconds or so after the power-down again! Repeatable boot, the boot, like the post-0.45A Power-down. .
It seems that this machine simple. . . . Power-down again after the boot, excluded the scope of a serious short-circuit fault may be a slight short circuit or circuit board to a supply voltage less. . . Pen on the table with an oscilloscope voltage power supply inductance, and then boot, the part of the PWM power supply waveforms are normal, thus, you can not rule out the voltage caused by brown-out causes. . . This machine is once again asked which part of the peer into the water, peers say that they can not have been clean for others, but moldy touchpad seemed to have a place, called peer-to C-shell brought to, after careful examination, it really was from the touch pad go on the water, while the touchpad is just below South Bridge chip, the location! Check around the South Bridge, but found no traces of the entering fluid. . . Given this machine had to repair than others, possibly others have been cleared clean. . . Would try to lay the South Bridge of the resistance bar. . . This resistance does not matter if a dozen. . . Several USB port resistance is different!
MINI PCI-E pedestal hit the data lines are not the same resistance, resistance plug CPU card, CPU pedestal to the South Bridge to play in all control lines are not the same! This shows that the South Bridge has been broken!
Decisively removed Southbridge, Hehe. Sure enough, inside has a serious mold, rusting. . . Although the last business clean-up, the surface is already clean as new, but he definitely will not see here, the edge has been horrendous. . . The following figure! So there will be a good repair since their own is not enough for others also repaired the psychological, the BIOS chip power resistors removed. . . Very wicked!
As the problem has found, the
easier to handle. . . Good clean-up pad, and put on a good Southbridge following figure:
Plug in the power supply, current 0.03A, plug in the VGA, try to power-up, current 0.5A jump after jump 0.93A. . 1.15A. . . . 1.34A. 1.10A, after jump off the screen has been shown to normal. . . Hehe. . This machine is almost fixed. Still in the hands of peers because of the hard disk and so on. Tell him to go on board to take tests, intelligence and good news. Everything is normal. .
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