Compaq Armada 4220T - charge while using

Hi,

I was given an old Compaq Armada 4220T laptop the other day and a charger
for it (don't think it's the original charger though)

Question. Is it possible to recharge the battery while using the laptop? I
ask because the charge light goes out when the computer is on and this makes
no sense to me as my other compaq laptop will charge while being used.

Any thoughts or suggestions appreciated.

Thanks.