Suspend works on battery but not on AC?

[Thin-king]

Hello everyone, first post here for me. I have a T23 with PCLinuxOS (KDE) and a just installed Debian Sarge (Gnome). Standby and suspend work fine (both hardware and software triggered) on PCLOS but in Debian I can only do a hardware Fn + F3, F4 standby and suspend. That's not much of an issue, I can live with that.

The problem is on Debian suspend works ok when on battery power only but on AC power it doesn't. Normally I get a quick *BEEP*, it powers down and the crescent moon LED lights up. But plugged in, hitting Fn+F4 I get a strange *DEE-DOO DEE-DOO* and the moon doesn't show up. I know it's not suspending correctly because it's still warm after a while and the fan even comes on periodically. It does however come back ok like from a normal suspend but gives a strange *BEEP-DAA-DAA* a little different from the quicker *BEEP BOP-BOP* on battery only. I hope these "beep" terms aren't too technical for anyone here. I couldn't think of any other way to describe the difference.

So does anyone have an idea what's going on or what I can check? I have APM (ACPI doesn't work at all) enabled ok if it's suspending fine on battery power but something about it being plugged in is stopping it from suspending correctly.