Laptop Will not boot

[Tech bud]

Dell XPS P54G

System: Laptop will not boot, nothing on screen. Get a power light on the power button. 3 amber light flashes one White light flashes. According to what I found this says cmos battery is dead.

I did the standard, tested the ac adapter and it tested fine. Tested the dc jack, it tested fine. Plugged in the dc jack and the leads are getting the power it is supposed to. Tested the power to the battery leads. They had 3.86 volts getting to it. So those tested fine.

I unplugged everything one by one to try and get power to the screen, with everything unplugged. Including the cmos battery. I still get no power to the screen. Comes on for a moment, cpu fan begins to spin then it just shuts down again.

Not overheating as it was off for some time, wouldn't have shut down so quick.

So motherboard, but how to know for sure? it does have another board that functions with the power button. Button how do you test the ribbon cable? I guess I can assume it does its job as it does try to turn the laptop back on.

Do you all feel its the motherboard also? Hate no power up issues as hard to really know which part is which. I always tell them at this point, its better to get a new laptop. Looking up the motherboard, its $350 for it and I could be wrong and its the cpu

 

[coffee]

Take your charger and measure the voltage on the middle pin. If voltage is missing on the middle pin or on the other side of the DC jack then your not going to boot up. You said the DC jack tested fine but I dont know what you have actually tested. If you just checked 19 v on the main rail you might have missed the middle pin. For Dell you should see about 14 volts.

If your looking at digging into this then take a meter and measure the voltage on one of your USB ports. Use the USB shield for ground. You should have 5volts. Laptops missing the 5v rail will appear to want to boot up but will power off quickly after the power button is pressed.

Next, Remove the cmos battery and short the positive and negative pads where the battery plugs in. Just takes about 10 seconds. In a lot of cases you can experience a frozen bios.

In a nutshell, The Keyboard Controller chip is sensing something not right and is shutting down the laptop.

Also, Check that you actually have 3v on the power button. If you do not then there is a problem with your 3v power rail.

This should get you started.

 

[Tech bud]

Take your charger and measure the voltage on the middle pin. If voltage is missing on the middle pin or on the other side of the DC jack then your not going to boot up. You said the DC jack tested fine but I dont know what you have actually tested. If you just checked 19 v on the main rail you might have missed the middle pin. For Dell you should see about 14 volts.

If your looking at digging into this then take a meter and measure the voltage on one of your USB ports. Use the USB shield for ground. You should have 5volts. Laptops missing the 5v rail will appear to want to boot up but will power off quickly after the power button is pressed.

Next, Remove the cmos battery and short the positive and negative pads where the battery plugs in. Just takes about 10 seconds. In a lot of cases you can experience a frozen bios.

In a nutshell, The Keyboard Controller chip is sensing something not right and is shutting down the laptop.

Also, Check that you actually have 3v on the power button. If you do not then there is a problem with your 3v power rail.

This should get you started.

So I test the AC adapter, its 19.5 volts. With it plugged into the DC jack, I unplug dc from the motherboard - I then test the red and black cables - they get the 19.5 volts. I plug the dc jack into motherboard socket - where it solders to the motherboard, it gets 19.5 volts. So I know correct power tis getting to the board.

So motherboard?

 

[Computer Bloke]

There's a bit missing.

You've told us that the error code indicates a CMOS battery failure and you've told us that it doesn't work with the CMOS battery removed, but you haven't told us what the CMOS battery's voltage is or what happens when you replace it with a known-good one.

So... did you try replacing the CMOS battery?

 

[Tech bud]

There's a bit missing.

You've told us that the error code indicates a CMOS battery failure and you've told us that it doesn't work with the CMOS battery removed, but you haven't told us what the CMOS battery's voltage is or what happens when you replace it with a known-good one.

So... did you try replacing the CMOS battery?

Can a laptop not boot with it removed?

 

[Tech bud]

It started haha

 

[Tech bud]

I had to leave the batter out longer

 

[Computer Bloke]

I had to leave the batter out longer

So the same technique can be used to fix computers and make a good Yorkshire pudding. What a wonderful world we live in!

 

[Tech bud]

So the same technique can be used to fix computers and make a good Yorkshire pudding. What a wonderful world we live in!

Correct, who would have thought haha