A21m not charging nor turning on with charger plugged in

[dvdmcwilliams]

Since i gave up for dead my first A21 i bought another A21 with a different problem: it only works if i charge the battery in the first a21 (with blink of death) and then i place the battery back in the new A21, do you think it could be a problem with the jack?, what other problem could it be if i sold back the jack and the problem persist? could i bypass this problem by having a dock station? does the notebook get power by the special dock connector or how it works?, thanks for the help!!