Extremely strange behaviour during standby

[aki74]

I have 3 ThinkPads T40 in the same, reinforced configuration: Dothan M735, 1.5 GB RAM PC2700, wifi Atheros A/B/G, HDD TravelStar 80GB, batteries >40000mWh. Of course: the latest ECP and BIOS. I love them. They used to work perfectly for a long time.

Unfortunately:
for the last 3-4 weeks one of them experiences a very strange behavior concerning the standby mode: when ordered to sleep it goes to the standby mode successfully but just after resuming (pressing the power button or opening the lid) it starts to prepare to the standby mode and switches to the standby mode once again. After next resume it wakes up and works correctly.

The interesting things are:
1. If the ultrabay is empty it always works OK. No matter which drive is in the ultrabay (I tried: DVDROM, CDRW/DVD and a new MultiBurner) the problem occurs every time.

2. The problem occurs only under Windows (I have an XP Professional). I tried several HDDs and several OSes from my other notebooks. Windows XP Professional from other ThinkPad -- the same. But under Linux (Arch and Gentoo) and FreeBSD there is no problem and I can see no errors in the logs!

3. I put the HDD from the "faulty" ThinkPad to another one and it works OK. It seems there is no problem with any single Windows instance. Both instances of Windows work perfectly when I mount HDDs in other ThinkPad. In this one -- the problem occurs for both HDDs.

4. There is no difference if the "faulty" ThinkPad goes to the standby mode by pressing the power button, closing the lid nor by power management. There is no difference if the battery is present: I tried only power,only battery, and both -- the same.

5. PCDoctor CD and similar tools show that there are no problems with this notebook.

Any ideas welcome!

Best regards,
Marek