Good to know. Might be time to seek out a dead one for cheap and see if it can be resurrected. Though I suspect many have battery corrosion issues that likely aren't such an easy fix.
In the US (which doesn't help you), a Nikon motor drive like MD-11, MD-12, or even MD-4 can be had from KEH in working condition for under US$30, and in as-is condition for just a few dollars. That's what happened with my MD-11, I bought it for about $3 to use as a grip and then decided to see if I could fix it.
Sometimes, you can get battery corrosion off by moistening battery terminals with vinegar and reaching in to scrape with a long handled screwdriver, but greater access is obtained by taking apart the MD. It's not really that hard.
For the MD-11 or MD-12, you peel back the leatherette on the lower sides and remove a bunch of screws to separate the top from the bottom. On the sides parallel to the battery holder, you only need to peel back a few mm from the top to access the screws; around the round grip part, you have to peel the leatherette up from the bottom. With all the screws removed, the top and bottom should come apart easily - if it doesn't come apart, you haven't found all the screws, I think 9 screws. But there will still be a couple of thin wires running down to the terminal for the MR-3 release, so don't break them. IME, although I've only taken apart a couple of them, at this point you may find that one of the wires from the guts of the drive to the back side of the battery terminal plate has come off - maybe that's the most common fault.
Here's a picture of what it looks like separated. You can see on the right where I peeled up the leatherette around the rounded side bottom in one piece. There are still two wires running down to the release terminal. However, the battery terminal plate, the squarish piece on the left, has a red wire running to it, but the other blue or black wire has come off and needs to be resoldered.