Computer needs several attempts to power on? (Much like a bad car)

Question

I've had a look at the available stack exchange forums and i have concluded that this one might be the most relevant for my question, though it does adhere to personal computing. Please inform me if this is the wrong place to ask this.

My question is perhaps a bit abstract. My laptop has in recent years had trouble turning on. But it hasn't been unable to turn on - it has just required a modest number of attempts! It's behavior when i want to turn it on has been very similar to that of a car which has trouble starting cold.

When i try to turn my computer on it will often require 10 tries or so, unless it has been on very recently (past 10-15 minutes). A failed attempt to turn on will activate the "Power ON" LED, and start turning the fan and then shut down after 2-3 seconds. If there is a CD/DVD in the disk reader it would start spinning too before the sudden shut down.

If the computer is connected to its power cord, it will after a failed startup reattempt to power on by itself after 2-3 seconds again. If it is merely connected to its battery it will just stay off after a failed attempt.

If it fails to turn on, it will not be able to power the screen before the sudden shut down! Thusly, once i see the screen backlight turn on and the "American Megatrends" logo, I know it has succeeded. Once the computer successfully boots it behaves normally.

This might be completely incidental, but i find that i have some increased luck to power it on while it's cold by tilting the laptop at different angles.

I am very much in the beginner, hobbyist stage of electronic doo-dads and blippety-bloops and don't fancy myself experienced enough to go probing around with my multimeter to find the fault - I simply don't know what to look for!

I don't have much hope for "solving" this (to me) negligible issue, but i find it extremely interesting! So i have come to you, the more experienced electronic engineers, for ideas on what might be causing this. Does anyone know what sort of components might be worn out, or what could be failing to cause this kind of problem?

Answer 1

I've had a similar problem with a PC. Once I turned it on it would restart after 2-3 seconds. What turned out to be the problem was that the power cable was slightly unplugged, and powered only part of the motherboard. To clarify, this is the power cable from the PSU to the motherboard in the case.

Now, there is no guarantee this is the exact problem you are having, but it looks like a power issue, if it can turn on properly. But usually with laptops it is cheaper to simply buy a new one.

Edit As other people have clarified it can be many things: a short somewhere etc. I do not think it is firmware related, because it boots properly after a couple of attempts. This means that the firmware is operating properly. I would say it is a mechanical issue somewhere e.g. cable being unplugged etc.

Perhaps you can open it up and look for some indicator LEDs, or an alphanumeric display, if you have one, when you power it up. Consult the motherboard manual.