Charging problem (90% sure mobo is damaged)

[Big Jim]

I have an Acer aspire series laptop here (yeh I know I know)

Customer report
Laptop won't charge, when plugged in it used battery
When powered on using just AC with battery disconnected it powers on only for a few seconds.
WHen switched off it appears to be charging


It was brought in with 73% battery after 30 mins charging switched off windows report 92% battery, so I have verified it can charge.
I power it on with AC still connected and all seemed ok until windows loaded then the battery and power lights both start flashing until AC is removed.
Charger tested ok
So I do a tear down, DC jack is NOT soldered to mobo, I disconnect harness and I can see on of the negative pins is badly burnt, however with AC adapter still connected I am getting 19+volts from it, same ith it connected to the mobo, I am getting 19+v off the back of the harness connecter.

Checked mobo over with magnifying lens, can see NO visible damage whatsoever. So I can only assume this has burnt something out at a circuit level, I am going to have to recommend mobo replacement unless anyone else has any bright ideas.

Cheers
James

 

[NYJimbo]

Try it with a known good charger that is rated the same or better than the amps/watts needed for the laptop (if in doubt go with 90 watts)