Hello, I recently received a used D600 that has some warranty remaining. Everything worked great for about a day (was left on the whole time) I used it on battery for about 30 minutes twice before returning to AC power. Then I decided to see how long it would last on battery and let it run down completely (about 3 hours) It then refused to recharge. It will charge for about 5 minutes then the AC adapter will shut off (green light on the adapter itself goes out) and start to run on battery. Doesn't matter it it's in BIOS or fully booted into XP. Runs fine on ac adapter alone, battery removed. Also runs fine on battery. AC adapter is properly detected as 65w model in BIOS, as is the battery. After the 5 minutes or so, the BIOS will go from charging to saying no ac adapter and battery status discharging. You have to unplug the adapter from and replug to get it to come on again. I know it's probably a faulty main board, but my symptoms seem to be slightly different than usual, and I don't have another AC adapter to test with. Could a faulty charging/main board cause the AC adapter itself to switch off? Or maybe the AC adapter is faulty and cant handle the current for charging the battery? Also read something about "resetting" the charging board, how to try that?