T42 switches between battery and AC power consistently

[jetmn]

My wifes T42 is having an issue where it will consistently switch between battery and AC power. It makes the dinging noise and the screen switches brightness, along with the icon switching. It does not do it extremely fast or in a rhythm. It may be ok for a min or 2, then start doing it about every 5 seconds, then stop again. It does not seem to matter if it is sitting on a table or not. Grabbing the corners of the palmrest do not seem to matter. I thought maybe it was a broken connection where the power supply plugs in, but it does the same thing in the docking station. I also tried 3 different power supplies (which all worked fine on the backup T30). I even tried switching HD's thinking it might be a software issue, but it still does it even with no OS installed.

I am quite stumped! Any help is appreciated!

After doing more searching it looks like this is the exact problem I am having! The laptop works fine on just battery or AC power, but has the issue when running on both. I also hear a pretty bad squealing noise from below the left side of the keyboard, around the S key or so. This noise happens only when on AC and battery is in.

http://forum.thinkpads.com/viewtopic.ph ... wer+supply

[jetmn]

Well, now it is doing it on AC only power too. It still is fine on just battery though.

[Pawelek]

Finally I have found the problem with my notebook. Unfortunaltely I do not think the solution will help in here. I use Win 7100 Ultimate with NHC and TPFanControl applications. Mine problem turned out to happen only when both applications were running. I ve been using only TPFanControl for more than a month and I hope an issue has gone. So for evenryone that use Win 7 : Dont use both of the programmes mentioned above simultaneously - only one can work fine.

Best regards
Pawelek

[jetmn]

I do run TPFancontrol on it, I will try turning that off! Thanks!

Edit: Nope, that didn't change anything.