External USB drive won't mount under Mavericks after upgrade

I have a 250GB Hitachi pocket-sized USB powered external hard drive which contains three partitions - two are Mac OSX Extended Journalled, while the third is a TruCrypt partition which I use to sync my data between my various Macs. While this disk also serves as a backup, it is not its primary role - I do that over the network via duplicity.

This drive mounted perfectly on my mid / early 2013 MacBook Pro running Mountain Lion. Last week, I upgraded to OSX Mavericks and yesterday, upgraded to 10.9.2 (which was a massive security update).

I just tried to attach this disk to the Mavericks MacBook and it does not register. The usual state of affairs is that the two mac partitions automount and I have to manually mount the TruCrypt partition. This time - nothing. That is nothing in Disk Utility either. The disk LED is lit, indicating that the USB connection is at least supplying power.

To make sure that it was not my hard disk or the USB cable that had conked out, I connected it to my old Snow Leopard machine. It mounted as before, without any problems at all. The LED even flashed twice as it usually does before a mount.

Interestingly, the Mavericks MacBook does recognize my FAT32 formatted flash drive as well as my old Nexus S smartphone. So, the USB mass storage driver (to borrow a term from my Linux machines) hasn't been shelved.

So, the problem is the specific combination of Mavericks and my external hard drive. To make a wild guess, are the USB ports not putting out enough power after the upgrade? I have no way of testing the hypothesis as I do not have the power connector for this hard drive - I have never needed it.

How do I access my hard disk from Mavericks? I am obviously not going to throw out a perfectly good working USB hard drive just because some Apple coder made a snafu somewhere in the OS code.