Laptop Charging problems

[Fantastic Dan]

I recently bought a car adaptor for my HP N5420L Laptop so I could use
my laptop on the road. When I plugged the adaptor into my cigerette
lighter, the LED on the actual charger did not light. I double checked
my ploarity and it was correct but still no change. Then I tried
switching the ploarity to see if it would have any effect, no change.
So I just figured the adaptor was faulty. However when I returned home
and plugged the laptop into the wall adaptor, the LED on the AC/DC
converter flashed dimmely and the laptop did not recognize a charge.
When I unplugged the charger from the laptop, the LED on the AC/DC box
lit up like normal... I'm getting quite worried that I may have some
sort of serious problem here. I haven't contacted HP yet, I figured I
would see if anyone knew if there was some type of simple fix or
anything for it.

Thanks in advance!

If you want to email responces, my email is [email protected], not
the one listed here.

 

[Sir Charles W. Shults III]

I recently bought a car adaptor for my HP N5420L Laptop so I could use
my laptop on the road. When I plugged the adaptor into my cigerette
lighter, the LED on the actual charger did not light.

This should have been the point where you stopped. If the charger does not
light in the first place, there is clearly something wrong.

I double checked my ploarity
*polarity*

and it was correct but still no change. Then I tried
switching the ploarity to see if it would have any effect, no change.

*Polarity*. Did you by chance plug your laptop into this thing at this
point?

So I just figured the adaptor was faulty. However when I returned home
and plugged the laptop into the wall adaptor, the LED on the AC/DC
converter flashed dimmely and the laptop did not recognize a charge.
When I unplugged the charger from the laptop, the LED on the AC/DC box
lit up like normal... I'm getting quite worried that I may have some
sort of serious problem here.

If you plugged the car adaptor into your laptop at some point, and
particularly after you reversed the polarity, it is very likely that you blasted
the circuitry inside the laptop. Probably only the charger circuitry, but
something has been damaged.

I haven't contacted HP yet, I figured I
would see if anyone knew if there was some type of simple fix or
anything for it.

If the charger was not an HP charger, you have murdered your warranty once
and for all. HP can be very snooty about this sort of thing, but now you
probably have unhappily found out why. No simple fixes for this; laptops are
cramped and often have very specialized components inside.
The power supplies often use very late model (or custom) switcher chips and
in any case are almost completely surface mounted these days. Even a good tech
will have a tough time. Your best bet is to plead ignorance to them, claim you
never used a car adapter, never knew such a beast existed, whatever. Let your
conscience be your guide.

Cheers!

Chip Shults
My robotics, space and CGI web page - http://home.cfl.rr.com/aichip