X61s card reader failure

[precip9]

I have several X61s, identically configured, running Windows 8. One has a bum card reader, failing to acknowledge the presence of a card -- any card. It's not a driver issue, because the Microsoft driver appears identically in Device Managere in all the machines. I tried cleaning it with some contact cleaner and multiple insertions, but no effect was noted.

Has anyone analyzed this failure mode?