Dell Inspiron 1420 power problem.

Hello everyone, having a bit of a perplexing problem here. I have 2 dell inspiron 1420 laptops. 2 weeks ago one of them stopped getting power and this week the second one got the same problem. This is what I have tried so far. I have tried switching the a/c adapters and that has not worked. I purchased a replacement a/c adapter and it will not work either. I have tried swapping batteries between them and nothing. I have tried taking the battery out completely and plugging in to the a/c adapter and tried to power on and I get nothing. I have tried every combination between battery and a/c adapter possible and I am not getting power to the laptops at all. I have tried different outlets as well to just cover my bases. The a/c adapters show their green lights when plugged in but I am just not getting power to the laptop. I was thinking it was maybe the jack as the soder connections sometimes break, and since the laptops are out of warranty and I am technically inclined I took one of them apart to check. The jack looks solid. The motherboard does not smell burnt, everything seems to be in order. I have done everything short of buying a new battery but I feel that even buying a new battery that the laptop will only function until the battery ran dead. Can anyone give me any suggestions on what they may think the problem is. I find it considerably odd that both laptops within a 3 week period just stopped charging all together and now won't even get power to start up. I know it will start up if I had a fresh battery but I think it would only last as long as the battery. If anyone has any suggestions or has had a similar problem and got it fixed.....anything at this point would be of help as this has really has me perplexed. Thank you in advance.

Sincerely

Stumped