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I have a strange issue with my Compaq CQ 61 running Windows 2012 (server) and I have Googled for it really long and hard and also searched other questions here but in vain. I believe my problem is a little unique.

Firstly, this laptop, unlike my other laptops does not run directly off an AC supply, so when I remove the battery and plug in the charger, it just doesn't turn on. At this stage there is a scope to doubt the charger.

Secondly, when I run it with a battery in the slot, it runs for hours without issues, so the charger itself doesn't seem to be an issue as well.

Thirdly, when the battery is in, and I disconnect the AC charger, the indicator goes from 100% to 0% in about 30 seconds and my computer turns itself off.

Any clues on what could be the issue? Please note that I have tried it with my original battery and doubting it, I have got a fresh new tested battery which works fine.

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Have you tried to use the laptop on another operating system, like Ububtu? –  Cfinley Jul 15 at 17:05
    
not yet, but changed from windows 7 earlier to windows 2012 recently –  skv Jul 15 at 17:32

3 Answers 3

You have a mostly-dead battery.

Not running without the battery is an unfortunate but common design choice that shackles you to spending money on a battery that may cost a significant portion of the current value of the computer when the battery becomes fully dead. For now, the 30 seconds of life it has is evidently enough to get started, so be happy about that.

The battery dying in 30 seconds is plenty of evidence that it's mostly-dead.

Buy a new battery, if you want battery operation, or if having it up and running is merely important to you. When the battery becomes all-dead, it won't start even with the power adapter. Wait, you bought a new battery, and you say that it works fine? Or are you saying that the new battery which you describe as "works fine" also dies in 30 seconds?

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Thank you for the answer, Sorry about the confusion, the new battery is what gives me 30 seconds the old one instantly dies, and I said its fine because I have tested it on another computer –  skv Jul 9 at 12:58
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Hmm. In that case I'd suspect a wiring problem/loose or dirty connector/cable inside the laptop. –  Ecnerwal Jul 9 at 13:27
    
Yes, as you mention this in the past in the same machine I have had a blinking caps + num lock (and no boot) issue, and my friend who is a hardware engineer tried to unwire the entire laptop and reassemble it, is there any specific area that you want me to focus on in case if we try it again –  skv Jul 9 at 13:33

It sounds like there might be a fault with the onboard electronics or power adapter and the battery is not charging.

In the case of the adapter it might not be providing enough power to charge the battery. An inexpensive multimeter from your local electronics store would be able to verify the output of the charger. Laptop adapters are pricey so it is tempting to order off-brand replacements. A knock-off adapter may produce extra noise, may not be certified, or may damage internal components. It also might not be producing enough power for the laptop to function properly. If you are using an off-brand adapter or see signs of inconsistent power output from the plug you may have your answer. Also while you're at it you should verify the output of the battery after the laptop's been off and plugged in for a while, too. If both the power adapter and battery are up to spec and the laptop is still dying, it's probably an onboard electronics issue.

If it is an onboard electronics issue it would be hard to pinpoint without some time and expertise. If you're sure the power adapter is OK and if the battery is in good condition/new then the most likely cause is a charging or power circuit inside the laptop. On the main board there are components that would have to be completely removed completely to be checked because they can't be tested in situ. These components include voltage regulators, resistors and capacitors. Sometimes manufacturers will make it easy and add test pads that you can measure but I couldn't find these listed in the service manual for your model. Replacement boards can be found on auction sites if all else fails.

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I will test this right away today and thanks for the detailed answer –  skv Jul 11 at 4:07

You can try a hard reset to see if it clears the issue. If not, it is likely a connection issue inside the laptop which sends power to the battery.

  1. Remove the battery
  2. Unplug the power and any USB devices
  3. Hold the power button down for 45 seconds
  4. Plug the unit back in but not the battery
  5. Start it

If it still won't start without the battery, It might be a good idea to have it serviced.

There are more things to try in this thread of the HP Support Forum regarding this topic.

The other options is to live with it the way it is.

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I have an HP laptop with a completely dead battery and it runs just fine without it, assuming I don't unplug it. –  Brian Jul 9 at 22:34

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