Category Archives: laptops

Zombie laptop

Lesson of the day: Some laptops don’t spin up CPU fans or switch on the screen when powering up

So I had a laptop which stopped working for apparently no reason. None of the lights came on except for the charger light when the battery & charger were connected. The power button didn’t do anything.

I assumed it was dead because the CPU fan wasn’t spinning up when pressing the power button (like in desktop computers.) I tried opening the laptop up, removing and connecting everything up outside of the case, which then got it working (second time around) The CPU fan still doesn’t spin up at boot time, so it’s pretty hard to troubleshoot the issue.

Basic Checks

Something you can try first is to find the documentation for your laptop/notebook. Go online and find the manuals for your machine. Try to find the service manual as well. This can be very useful.

First of all, check your battery. If you’re lucky and you have a friend/neighbour who has the same kind of laptop, you can test your battery with their machine. Otherwise, get hold of a multimeter and check out the voltages and currents coming out of the battery terminals. Sometimes (for example on an IBM Thinkpad) the expected voltages/currents are written in the service manual. This way, you can tell if the battery is dead or not. If your battery isn’t dead, it should allow you to start the laptop, even if the charger is having problems.

Check your charger. Again, if you have a friend/neighbour with the same machine, ask them to test the charger. It’s possible, but not very safe to check if you’re getting any voltages/currents out of the charger terminals with a multimeter, just to see if it’s supplying any power or not. Check if the fuse has blown on the charger’s plug.

Sometimes your charger is fine, but the charger connector on the laptop is messed up. In this case, you’ll have to wiggle the wire around, and hold it until the charging light shows. Make sure the battery is plugged in when you do this, otherwise the charging light wont show at all. Sometimes, a bit of pressure upwards/downwards or sideways does the trick and gets your charging light showing again.

If you are sure your battery isn’t dead, your battery holds charge, and/or your charger is working, then you can try the power button. Try holding it down for a couple of seconds, and wait around 10 seconds to see if it’s having any effect.

If your power button isn’t helping, you can try reseating the RAM module. You should consult your manual (or google) on how to do this.

If re-seating RAM doesn’t help, try removing and reinserting the hard drive.

You may have a problem with the graphics card/display. Some machines overheat after long periods and this screws up some of the parts which get hot, such as the graphics chip.

Surgery

Your laptop isn’t worth spending a lot of money on to have it repaired? Take it apart and have a closer look. You’ll need a service manual to do this the first time, because some of the screws and tabs and stuff are hard to spot, but you can get the thing open without it if you try hard or google. Keep a log of the order in which you take out screws, and keep each group of screws seperate. For example, I’d write,

Step 1: remove 3 screws securing keyboard to top of case, and then place them together

This way it makes it alot easier to put it back together, you just follow the steps backwards. Don’t lose/mix up the screws, you won’t remember which ones go where. Trust me.

Having a working battery and charger is useful when you’ve opened up the laptop, and want to check if the board is fried or not, by checking the lights on the laptop.

This one time..

I just took the whole laptop apart, out of the casing and connected up the battery and charger. This is quite a dangerous thing to do. It can easily short out and fry the board/components or give you an electric shock.

I was getting an orange charger light if I pushed the charger cable down in the charger socket. The charger port was dodgy and needed replacing.
There was a green light with a plug icon above it which flickered green when I applied power. When I tried the power button, I got nothing.

When I took it apart, there was a small daughter board attached to the motherboard, which I’ll call the power board, into which the charger went. This board was connected to the main mother board via a connector with about 20-40 golden pins.On my machine this was the problem. When this power board was connected, and held up at an angle, and the charger cable pushed down, I began getting a green power light.

At this point I connected the hard drive, RAM and keyboard, and the hard drive began whirring.

Once it worked, I put the machine back together.