Member Avatar for kenjoearl

OK, so I've got a Gateway FX P-7805u laptop with power up issues. Here's the whole story:
One day, even though the laptop itself was plugged into the wall, when I hovered on the battery indicator, the windows 7 notification said "plugged in, not charging" and the battery was stuck at around 20%. I did some research, and found what looked like a fix for the problem. Basically, uninstall the battery drivers in the control panel, then shut down and power up. I did so, but when I went to power up, nothing would happen. I tried all the obvious things, unplugging, holding down the power button for a minute with no battery or power, etc... and nothing would to turn it on. However, when the battery is in, and it is plugged in via the AC adapter, the battery charge light turns on.
Eventually, in my troubleshooting, I got to this point. When I disconnect the cmos battery, and reconnect it, with no power connected to the laptop, then plug in the power to the laptop, it immediately powers up, without pushing any buttons or anything, and everything runs just fine... BUT, I can then not turn off the laptop by pressing the power button itself, no matter how long I hold it down or how many times I press it. The power button seems to do nothing at all. I can then shut down the computer, by going through the start menu, and after it has been shut down, the only way to get it to power on again, is by disconnecting the cmos battery, reconnecting, and then plugging it in.
I have taken additional troubleshooting steps since then also, I took off the plate with the power button board on it,re-seated the zif connectors, to no avail. I connected up a continuity tester to the two small solder spots on the sides of the power button on the bottom of the board, and when I press it, it does make a connection(I had originally thought it was that power board), but I don't know enough about electronics at this point to go any further.
It's really frustrating to be so close... knowing how to turn it on, and having it actually work perfectly once it's on, yet not having a clue which part to replace to get it working again. I think it could easily be the motherboard, just having a problem interpreting the power switch signal too.

Anyway, any insights or help would be much appreciated.
thanks!

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, the way it autostarts only after you pull the CMOS and reapply AC, while the power button never responds, points away from Windows and straight at the hardware path from the button board to the embedded controller. A 4‑second hold should still force a hard power‑off at the firmware level; if that override never trips, the PWRBTN signal is not reaching the EC or the EC/power circuitry is unhealthy. That aligns with what and suspected. (uefi.org)

On the FX P‑78xx, the power button lives on its own small board under the keyboard cover and connects via a white ribbon. Reseat both ends, inspect the ribbon for cracked traces, and meter it end‑to‑end. If you are comfortable, with battery and AC removed, briefly short the two power‑switch pins at the motherboard header to simulate a press; if the system then reacts when AC is reapplied, replace the button board/cable. Gateway’s service guide documents the separate power button board, its FRU, and the keyboard‑cover power‑button cable/connector you reseat. (scribd.com)

While you are in there, rule out basics: use the correct 120 W adapter this model shipped with, and verify 19 V under load; using a lower‑watt brick can cause flaky power behavior. Also check the CMOS coin‑cell; if it reads under roughly 2.8–3.0 V, replace it with the specified Gateway part rather than assuming it recharges. The service guide shows the CMOS battery replacement and cautions to use the model‑specific pack. (scribd.com)

If you see corrosion or darkened caps near DC‑in or the charger area, that is classic liquid‑damage corrosion and can break both charging and the button path. At that point, a system board swap is the practical fix on this platform. (support.swarthmore.edu)

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Member Avatar for mjdodd

the power button is not just a power button. It is itself controlled by software so that the machine can go to sleep turn off and also reboot etc. So that software also has to be kept alive when the machine is off (and that relies on the internal battery and the cmos battery. is your cmos battery OK (they should recharge, but a failing cmos battery will give the symptoms you have had!
if it not that then most likely a mobo fault and that needs special equipment to test it.
M

Member Avatar for kenjoearl

Thanks, I'll see about the cmos battery. My best guess at this point is exactly as you mentioned, something wrong with the motherboard.

Member Avatar for junny4u

The power unit on the MOBO could be the fault! In most cases, you'd be better off replacing the MOBO.

Member Avatar for jedjick

i saw your comment it is nice for more information about this topic plz contact your friends & relatives.

Edited by Dani because: Plug snipped
Member Avatar for kenjoearl

Well, I've taken the thing apart, looked at it, and actually found a spot on the motherboard that looks to have been burned out at some point. It has corrosion on it, and a couple of small caps seem to have been blown out (they're black on the ends)... I'm going to assume the mobo has gone bad. Looks to have been perhaps a spot where something spilled at some point, even though I don't remember ever spilling anything on it. So, I'm chalking it up to a dead motherboard. Thanks for the comments.

Member Avatar for jedjick

hey friends..

the power button is not just a power button. It is itself controlled by software so that the machine can go to sleep turn off and also reboot etc.

So that software also has to be kept alive when the machine is off (and that relies on the internal battery and the cmos battery. is your cmos battery OK (they should recharge, but a failing cmos battery will give the symptoms you have had.

Edited by Dani because: Plug snipped
Member Avatar for racheleuber

I turned my laptop on it booted up halfway then turned off , the I plunges in again for about a hour then I turned it on and went half boot , firm off

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