Laptop won't power on. High current output from charger.

[magnabolt]

Hey! So, I was formatting this Acer Extensa 4630z laptop for my aunt. Currently it doesn't have a battery, so I am running it directly from the power adapter. The laptop was running fine, but since the last time shut it down I haven't been able to power it up. No matter how many times I re-plug the adapter pin and press the power button.

My aunt told me that this has happened a few times before and that when this happens she just lets the laptop sit for a while and presses the power button now and then and the laptop randomly powers on.

The power LED on the adapter does light up, so I thought I might as well check for output on the charger pin. The adapter is rated for 19V, 3.43A output, but my multimeter showed 7.8A output. The voltage output was fine at 19.6V. Why is the current output so high? Is this the reason the laptop refuses to power up?

Please help me out here.

 

[getochkn]

You can't get a good measure of current unless it's under load.

 

[magnabolt]

You can't get a good measure of current unless it's under load.

Does this mean that even though the adapter is rated at 3.43A it might output more current when the laptop is under load?

Is there any other reason for the laptop to not power on?

 

[mbarnes86]

Hi

Maybe it should have a battery fitted even if it does not last long on a old battery

You should not measure no load current through the meter
It has a low resistance and may be damaged
Also you can't measure current and volts at the same time with one multimeter
If you overload the psu it should shutdown yours did not

The voltage may drop so total watts is less than 19 x 3.43 65 watts


Often on faulty old laptop motherboards removing battery and psu connector
Then press on button for 10 to 20 seconds discharges some capacitors

It may then start ( for a while )

Regards
Mike Barnes

 

[magnabolt]

Thank you for your detailed reply.

Hi
Maybe it should have a battery fitted even if it does not last long on a old battery

Okay, I will try with the battery inserted.

You should not measure no load current through the meter

Thanks for the tip!

It has a low resistance and may be damaged

What might get damaged?

Also you can't measure current and volts at the same time with one multimeter

Yeah, I did not measure it simultaneously.

If you overload the psu it should shutdown yours did not

Btw, the laptop used to randomly shutdown sometimes. My aunt was running Windows XP which had become horribly slow (high system idle process cpu usage), which is why I am formatting it.

The voltage may drop so total watts is less than 19 x 3.43 65 watts

I see.

Often on faulty old laptop motherboards removing battery and psu connector
Then press on button for 10 to 20 seconds discharges some capacitors

It may then start ( for a while )

I tried this but it didn't help start the laptop. The laptop is quite old. The original battery was replaced because it couldn't retain charge. The second battery worked fine for 6 months then it couldn't retain charge for more than 15-20 mins. Also, my aunt told me that it doesn't matter whether the battery is connected or not, it just won't power on sometimes.

What should I do to fix this?

 

[mbarnes86]

Hi
If this laptop originally came with XP it is so old that it is beyond economic repair by professionals .

It probably needs a new motherboard

Buy a new or newer laptop with win 7

regards
Mike Barnes