Laptop only boots on AC Power

[noTe]

I recently bought a laptop from a friend (Thinkpad R51) and it works great when plugged in.... but it will not boot up unless I have it plugged in.

While it is booting up I can unplug the AC power cord and it runs off the battery without any issues. I've tried replacing the battery but the laptop still does the same thing...

My friend said he'd take back the laptop since I've been having issues. He thinks it's a bad board in the laptop but I just wanted to check on here to see if anyone had any suggestions because I really want to keep it if possible.

Thanks!

[RyderOCZ]

I do not understand. If you power it on while plugged in, it turns on, but then you can unplug and it finished booting to Windows fine on the battery?

If you try to power it on with just the battery, it doesn't work?

[Movieman]

I do not understand. If you power it on while plugged in, it turns on, but then you can unplug and it finished booting to Windows fine on the battery?

If you try to power it on with just the battery, it doesn't work?

maybe not enough juice in the battery for the initial kick(surge) but enough to run??:confused:
I'd try to borrow a known good battery first before I did anything else.

[Nate P.]

I have a Gateway 450ROG laptop with that EXACT same issue. Strange...

[Sparky]

When you power it on with the battery only, what does it do? Try and boot and fail, or not even POST, or what?

[littleowl]

dead battory have to buy a new one

[dinos22]

when you say you've tried replacing battery
was it for a new one?

have there been any upgrades on components done on the machine (like CPU etc..)?

[Nate P.]

For mine, I won't even power up with battery only. Will work absolutely fine with AC power. Thought the battery was dead, got a brand new replacement, and same thing happened.

[noTe]

I do not understand. If you power it on while plugged in, it turns on, but then you can unplug and it finished booting to Windows fine on the battery?

If you try to power it on with just the battery, it doesn't work?

Correct.


maybe not enough juice in the battery for the initial kick(surge) but enough to run??:confused:
I'd try to borrow a known good battery first before I did anything else.

Tried a different battery and it did the same thing. Even took the battery that came with the laptop and put it in another laptop and it started on battery power. The issue is for sure not the battery.


When you power it on with the battery only, what does it do? Try and boot and fail, or not even POST, or what?

Nothing happens on the screen, you hear the fan inside the laptop turn on for a split second and then turn off. Also, the power light stays solid for the split second as well.


dead battory have to buy a new one

As I said in my first post, switched batteries and it does the same thing.


when you say you've tried replacing battery
was it for a new one?

have there been any upgrades on components done on the machine (like CPU etc..)?

I know the LCD screen and a fan inside the notebook was replaced. That's all I know of. I'm pretty sure nothing is upgraded because the specs on the machine in Windows match IBM's factory specs.

[dinos22]

it must have something to do with those hardware changes either in assembly or spec of parts

[tiro_uspsss]

my guess is the mobo, or a component on the mobo

[ak_47_boy]

I would guess the bios or w/e is reading the battery voltage incorrectly on start up. Once it is started the OS takes over the job of battery monitoring. Try to flash the bios to the newest version.

[Tortel]

Maybe bad BIOS settings? Turning on stepping/ect might help, but Im no expert