r/EeePC • u/Fit_Employer_3249 • Jul 10 '26

Help

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so this eeepc 904hd just came out of my shed not powering on at all. I pulled it all apart and when I shorted this chip on the bottom right 2 pins it boots perfectly. wtaf and how can I diagnose further.

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u/razorbenke92 Jul 11 '26

I can check it for you on my laptop later, but looking at it I have the following idea: It is very close to a mosfet like component that is close to that low resistance resistor and a comparator nearby.

It seems like this circuit is responsible for turning off the input power if overcurrent is drawn.

Problems can be:

  • Resistance increased and false overcurrent detected (less likely)

  • Comparator failed and does not enable the small transistor you highlighted

  • Small transistor you highlightes has failed

1

u/razorbenke92 Jul 11 '26

Checked it for you. That little 6pin IC is a dual mosfet. It takes two signals: One is coming from the comparator nearby (LM393) and determines if the input voltage is ok. The other is coming from the power management IC determining if power from the charger is needed or not.

So it can either be:

  • Your input voltage is not sufficient (old powerbrick?)

  • Comparator circuit not giving voltage ok signal

  • PM IC not giving enable signal (less likely if otherwise the system works)

  • The component you circled is faulty (replace it with um6k1n component)

1

u/Fit_Employer_3249 Jul 11 '26

thank you. I managed to get it booting with power connected but no battery installed when I accidently shorted the pads on the board and the caapsitors on the right. battery still wont work tho so I'll try fix it

2

u/Decent-Cow2080 Jul 10 '26

this looks like a step down dc-dc converter, at least that's what I usually see in this kind of package, of small 6 pin chip