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标题: HP DV7 no standby pwm voltage [打印本页]
作者: vusalcrm    时间: 2020-5-3 21:52
标题: HP DV7 no standby pwm voltage
本帖最后由 vusalcrm 于 2020-5-4 00:56 编辑

Model: HP Pavilion DV7
MotherboardCode: Quanta UT3 DIS Only

Hello to everyone
A laptop came to my service. Motherboard does not start. I connectedit to the power supply.
I connectedit to the power supply . Standby mode 0.004A . I started measuring.


1. Measuring VIN +19V –OK. Both mosfetswere open. +19 voltages were shared on the motherboard
sek1.jpg
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2. Then I measured the values of the standbypwm coils (PL8 and PL9)
PL8 > +5VPCU = 2.3K and PL9 > +3VPCU =3.1K (an average value) no short circuit.

3.  I reconnected the power supply and imeasured the supply voltages.
PL8 > 0.507mV PL9 > 27.3mV ( this is not normal )
sek2.jpg
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4.  Standby voltage controls on the motherboard PU2 (RT8206B)
Need to die the main voltage coming to the chip first. Measuring RT8206B 6PIN. Low voltage passes across the resistor to the other side. PR22 1R resistor SMD Code 1R0 . Measured the resistance (PR22 – 137K) this is not normal.

I measured the LDO voltage (RT8206B PIN7). There is also strangeness here. (Normal voltage LDO +5.0V)

Replace resistance add 2R2 (2.2R). +19 voltage fully input.

Connected the power supply. there is also strangeness here. standby mode 0.049A . There is a short circuit

I examined with thermal camera and the heated PWM RT8206B.  Changed PWM.

Connected the power supply everything is normal standby mode 0.007A . Voltage normal at standby coils

And the expected moment has come
Happy Ending...

Note: The problem with this motherboard is due to low quality adapters.
such products often damage laptops. I met often

Good day...

作者: H55    时间: 2020-5-3 22:04
And the expected moment has come
Happy Ending...

RT8206 报废！ 干掉
激动人心的时刻 来了，亮鸡！！  完美收工。。

你是那里的。。美国的？？ where are you from ？ USA?   Young Boy ?
作者: 天意wx    时间: 2020-5-3 22:08
欢迎外国的维修朋友 欢迎在论坛分享相关维修案列
作者: wangxinzhou    时间: 2020-5-3 22:12
咋一股大碴子味儿？
作者: 趁买内    时间: 2020-5-3 22:26
全文没用翻译看的。全部靠自己三脚猫英语水平看完的。理解个90%。待机芯片烧了。导致PR22 保险也烧了。就这样。你就给你加分了
作者: 湖北小涛    时间: 2020-5-3 22:35
部靠自己三脚猫英语水平看完的。理解个90%。待机芯片烧了。导致PR22 保险也烧了。就这样。你就给你加分了
作者: Aisky108    时间: 2020-5-3 23:25
cool work, and glad to see . so, welcome to post more.
作者: 见习维修8    时间: 2020-5-4 09:37
学习了，谢谢，东西真全
作者: vusalcrm    时间: 2020-5-4 20:21
H55 发表于 2020-5-3 22:04
And the expected moment has come
Happy Ending...

i am form Azerbaijan
作者: liupinganxinkej    时间: 2020-5-6 22:15
欢迎外国的维修朋友，有点看不懂
作者: 71850811    时间: 2020-5-7 01:15
英语太差，看不懂
作者: pjkx    时间: 2020-5-7 09:08
欢迎外国朋友。
作者: ▌盛夏的火▌    时间: 2020-5-7 11:02
是一位国际友人，写的很有水准
作者: chouwanqing    时间: 2020-5-7 21:21
欢迎国外友人分享！！！！
作者: falwny2018    时间: 2020-5-7 23:40
技术无国界。
分析得详细。
作者: 喻庆国    时间: 2020-5-8 01:37
这外国朋友的装备还是不错的，就是维修水平比起中国人来说还是有很大距离的！要不说中国人了不起，做技术全球除了中国人日本人基本上没谁了。



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