Well after recording my first concert with the MR-1, I ran into battery problems, despite being amply forewarned from these threads.
I read the threads on plugging in an external battery. I have the free battery pack that Korg gives for it, but I also have a Li-Ion USB battery pack that I bought as a backup power for my iPod. I have the APC UPB10 (
http://www.amazon.com/APC-UPB10-Universal-Battery-10WH/dp/B000GBN42E), but any USB battery pack should work.
From the info in this thread, I reasoned that a usb charging cable for the Sony PSP would connect the battery pack to the MR-1:
http://taperssection.com/index.php/topic,87354.0/all.htmlbut I didn't think it would be cost effective to get all the parts from Radio Shack or Fry's to make a USB -> Power plug cable.
Searching on eBay, the cables were cheap, but the shipping was outrageous.
I found this Y-cable from DealExtreme that does exactly what I want, for a grand total of $2.40 (free shipping).
http://dealextreme.com/details.dx/sku.8693Not only that, but you can plug in both the USB and power on the MR-1, then to the USB on your computer, and both charge the battery and mount the drive.
Plugging it into the battery pack, it gives the "charging" icon, so I assume it is working.
The only problem with DealExtreme is that it takes forever for them to ship the item. I ordered it on Jan 23, and only received it today (Feb. 12). They are based in China, but I have had no problems with them. I've ordered 3-4 things from them without a problem, only long wait times.
Anyway, hope that helps anyone looking to power the MR-1 with an external USB battery pack, or wanting to charge+mount the device with just one cable.