宏基4738进水修复

会员652681

      今早接一台宏基4738进水本子，果断拆机目测键盘下一片不明液体痕迹，腐蚀了不少零件，郁闷的是好像进水已有不少时间了，洗板水洗了N遍都没把它消灭干净。

     废话不说直入正题，打了下公共点等各大供电阻值基本正常，准备上电看看，电流0.00V，直奔EC待机，

[img]file:///C:/Documents%20and%20Settings/Administrator/Application%20Data/Tencent/Users/348133077/QQ/WinTemp/RichOle/9$[O%7D3~W6(AEPSVLH)B%7B188.jpg[/img]

万用表量了下RT8206工作条件，发现VIN过两电阻分压给4脚线性电压开启信号木有电压，找到PR135和PR134两电阻，其中PR135一端连VIN脚腐蚀断线了，找了个360K电阻飞线到PWM上管，此图共有两处飞线，

file:///C:/Documents%20and%20Settings/Administrator/Application%20Data/Tencent/Users/348133077/QQ/WinTemp/RichOle/~5VA7UYPHJ@@C%7D%255%60~%60_Q94.jpg [img]file:///C:/Documents%20and%20Settings/Administrator/Application%20Data/Tencent/Users/348133077/QQ/WinTemp/RichOle/4(S03[KUFH9C40LG(3OG5QQ.jpg[/img]

PR140是VIN分压电阻，未触发时VIN通过PR140和PR141两电阻分压得到高电平控制PQ19导通拉低S5D信号,不使PQ15在上电时就导通，PR140明显发黑直接与PR135一起飞线了，上电待机0.07V，打了下EC待机阻值正常。瞅了瞅各处腐蚀的地方，差点亮瞎哥的火眼金睛，网卡接口黄绿灯好耀眼，兰花指抚摸了下网卡BCM57780，风枪啪的一声把它干掉了，

[img]file:///C:/Documents%20and%20Settings/Administrator/Application%20Data/Tencent/Users/348133077/QQ/WinTemp/RichOle/(KQ_QW[8DX(79VPDT]V9%25G6.jpg[/img]

上电待机正常了，按了下开关，没点反应，EC待机正常直接查LID，适配器检测，开关跳变，RSMRST#等信号，发现LID信号为低电平，找到HE1发现断了一个脚，取掉直接1,2脚相连。

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上电触发后电流到0.4掉电，抓了各大供电波形都正常，查供电PG，

file:///C:/Documents%20and%20Settings/Administrator/Application%20Data/Tencent/Users/348133077/QQ/WinTemp/RichOle/RB2Q]D@95D6ZWPO%7DS%60YWOA0.jpg

发现上拉电阻R110连接+3V处没电压，+3V是3VPCU转换电压，量了下电阻，没发现断线，估计是缺这电压了，继续翻图，

file:///C:/Documents%20and%20Settings/Administrator/Application%20Data/Tencent/Users/348133077/QQ/WinTemp/RichOle/T2ZK2VH(F4EGV6PBGAKC)RI.jpg

找到PQ58测量4脚控制端没电压，查找MAIND信号来源，

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此信号是由线性自举电压15V通过PR123上拉，实测为12V左右，PR123腐蚀掉件了，料板上找了个200K电阻代替。

file:///C:/Documents%20and%20Settings/Administrator/Application%20Data/Tencent/Users/348133077/QQ/WinTemp/RichOle/5)9B@2IV09D)%7DZN]TV(RVMD.jpg

上电触发后显示正常，心里小小的高兴了下，可好景不长，两小时后掉电到0.6。蛋疼啊~  从新上电风扇居然自动转起来了！按开关后电流到0.6上不去了，果断沿着风扇供电查找，

[img]file:///C:/Documents%20and%20Settings/Administrator/Application%20Data/Tencent/Users/348133077/QQ/WinTemp/RichOle/OA%7B04[BB8J~(ASNIU)K5ECV.jpg[/img]

还是MAIND控制信号在搞鬼，待机时MAIND控制信号就为高电平开启了后极+3V供电，所以上电风扇自转，查找控制来源，

[img]file:///C:/Documents%20and%20Settings/Administrator/Application%20Data/Tencent/Users/348133077/QQ/WinTemp/RichOle/EX7KBR_H1TR81[02%60U718G7.jpg[/img]

之前说过MANID信号由15V上拉，而此信号在未触发时由VIN经两电阻PR128和PR136分压得高电平控制PQ25导通拉低，而触发后由EC发出的MANON高电平信号控制PQ26NPN管导通拉低VIN分压而来的电压以控制PQ25N沟道管不导通来控制高电平MAIND开启3VPCU转换电压。其中PR128腐蚀与VIN断线，换了两个10K电阻代替PR128和PR136。

[img]file:///C:/Documents%20and%20Settings/Administrator/Application%20Data/Tencent/Users/348133077/QQ/WinTemp/RichOle/YBV~%7BE%25WJZK@MKF)%7B[04S2I.jpg[/img]

上电不自转了，蛋疼的事又来了触发后电流跳到1.3几不显外接显示。量屏接口无LCDVCC供电

file:///C:/Documents%20and%20Settings/Administrator/Application%20Data/Tencent/Users/348133077/QQ/WinTemp/RichOle/6SE02%7B92L)99~L5)R9(0(UN.jpg 查找来源[img]file:///C:/Documents%20and%20Settings/Administrator/Application%20Data/Tencent/Users/348133077/QQ/WinTemp/RichOle/W]]MO%7B%7DD%608DU3T)B9B25@IJ.jpg[/img]

LCDVCC由U1输出，表笔测量3脚控制开启信号为低，此信号由显卡过电阻发出，直接1，6脚相连

[img]file:///C:/Documents%20and%20Settings/Administrator/Application%20Data/Tencent/Users/348133077/QQ/WinTemp/RichOle/XXZ(%25IW5OPRRGV[L(O(%60GGL.jpg[/img]

开机涛声依旧，懒得打值了，直接BGA干显卡

[img]file:///C:/Documents%20and%20Settings/Administrator/Application%20Data/Tencent/Users/348133077/QQ/WinTemp/RichOle/Q$~43CGO46A8MYE[_KMK(RP.jpg[/img]

正常亮机！测机一天让客户拿走了。

   首次发帖望各位大神们赐点分吧！实在没分下载了

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