I have a ThinkPad T470 that will not boot when the CMOS battery is plugged in.
With only the fan, a RAM module and a USB-C monitor attached, but no CMOS battery, it starts up normally, i.e. after about 90 seconds and two reboots, it stops with a message to press F1 to enter date & time.
If the power is switched off and a CMOS battery is inserted, it restarts as described above. However, after switching it off and on again, it does not turn on. It draws almost no current and shows no sign of life.
I used a different CMOS battery and checked the components around the battery socket, they all look fine. RTCRST to GND is 1 MOhm. I then flashed a cleanME BIOS and finally a BIOS from another working T470. None of this has helped.
Any advice is welcome.
Schematic is here https://www.badcaps.net/forum/showthread.php?t=78951
With only the fan, a RAM module and a USB-C monitor attached, but no CMOS battery, it starts up normally, i.e. after about 90 seconds and two reboots, it stops with a message to press F1 to enter date & time.
If the power is switched off and a CMOS battery is inserted, it restarts as described above. However, after switching it off and on again, it does not turn on. It draws almost no current and shows no sign of life.
I used a different CMOS battery and checked the components around the battery socket, they all look fine. RTCRST to GND is 1 MOhm. I then flashed a cleanME BIOS and finally a BIOS from another working T470. None of this has helped.
Any advice is welcome.
Schematic is here https://www.badcaps.net/forum/showthread.php?t=78951
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