X61T always does extended memory test

[K0LO]

Haven't been on the forum for quite a while. I wonder if any of you can help me figure this out. My ThinkPad X61 tablet (7764 CTO) is set to do a quick memory test in the BIOS settings and has been for 6 years now. Despite this, it will always do an extended memory test at power-on. You can observe this by pressing the ESC key at power up to see what it is doing during POST. Doing an extended memory test delays startup by quite a bit, and POST on this machine was always dog slow. Now it's double-dog slow.

More information/clues:
1. If you turn on the power, then power down a few seconds later while the memory test is running, then immediately power back up, the unit will do a quick memory test like it should. This led me to suspect a weak CMOS battery. The CMOS battery was 6 years old and I just replaced it with a new one and nothing changed.
2. I've run MemTest on the RAM with no errors found. Also cleaned the contacts on the modules to no avail.
3. I've cleared CMOS then reset all of the BIOS settings. Still does it.
4. This started as soon as I upgraded the OS from Windows 8.1 to Windows 10 in the beginning of August , although I can't see how the OS could gain control of the BIOS settings and force an extended memory test.

Anyone have any ideas or suggestions?

[thinkpadcollection]

This could be a bit rot in bios or cmos memory section. I had a TV behaved that way and fixed it by replacing both microcontroller & 8 pin NVRAM chip.

This means check cmos battery voltage if not, motherboard the issue.

Cheers, thinkpadcollection, was a TV tech repair.

[Bibin]

You could first try resetting to default settings then putting back what you want. I know the setting is correct, but there could be other bits set in there which are not visible.

[wileE]

There is a T61 and R61 with the same problem after a Windows 10 upgrade on the german forum.

Do you have the Middleton BIOS on your machine?
Have you tried to flash the BIOS again?

[K0LO]

Great suggestions, guys:

Bibin: I did reset to default after replacing the CMOS battery and before customizing the BIOS settings. Didn't help.
thinkpadcollection: I did replace the CMOS battery. But it may be bit rot. See next item below.
wilE: Good suggestion about flashing the BIOS. I was going on the assumption that there might have been a problem with the NVRAM cell that was storing the bit for quick/extended memory test, so I re-wrote it several times to no avail. However, it didn't occur to me that there might be bit rot with some portion of the BIOS code that is responsible for checking the memory test setting. That makes perfect sense, so I'll try a re-flash.

To answer your other question, no - I am not using the Middleton BIOS. I'm using the Lenovo BIOS version 1.24 dated 10-12-2009. I see that there is a newer version 1.25 dated 4-19-2011, so I'll probably use that for the re-flash.

Your comment about the T61 and R61 having the same problem is very interesting. At first I thought it was a coincidence when it happened right after upgrading to Windows 10. Since then I have searched for similar reports but didn't find any. My thought was that if this was somehow caused by Windows 10 then there would be lots of posts about it. Since I didn't find any, I dismissed the thought. But I'll try to do more searching.

[K0LO]

Re-flashing the BIOS fixed this issue. I used version 1.25, but had forgotten what a pain it is to flash this model Thinkpad without a docking station http://www.thinkwiki.org/wiki/BIOS_Upgrade/X_Series. But mission accomplished using a variation of approach 3 (mount the Lenovo ISO, copy the files to a bootable DOS flash drive).

Thanks to everyone for their suggestions.