T410 will not go to Standby by closing lid

[CrendKing]

I have a T410 and suffers similar issue as this post. I set the "Lid closed" action in Power Manager to "Sleep". When I close lid, nothing happens. I can still see the screen light. I recall this issue starts after a depot repair service months ago.

I also observe the same issue in Linux. Therefore I think this is a hardware problem.

I posted a question in Lenovo Community, but only get a useless answer.

In T410 Hardware Maintenance Manual, under Keyboard Bazel there is a miscellanous part named "Magnet, suspend switch". Is it related to this issue? Can I fix this by glue a magnet somewhere?

Thank you in advance for your help. This is really annoying.