After Apple replaced my 2 gigabyte first generation iPod Nano with a nifty little 8Gb sixth generation model (due to a product recall), I found myself using that in preference to my Cowon X7, even though the latter has 160Gb storage. The consequence of this is that I allowed the X7 to completely discharge.
No problem, I thought, just charge it up again. But no! Things are not that simple. It transpires that the Cowon firmware doesn’t take kindly to a fully discharged battery, and won’t let it charge. I did a spot of Googling, and discovered a suggested solution - to connect it to the charger for a long period - 100h was mentioned.
Well, I tried that, to no avail.
A second suggestion was to open up the case, and briefly short out two wires that connect the main circuit board to the battery. This then resets the system so it can charge the battery. Opening the device was quite tricky. It’s held together by four tiny T6 torx screws. A visit to the workshop, and the screws were out. The two halves of the case are clicked together, and took a bit of leverage to separate. This done, the innards are exposed - everything remains attached to the front of the case.
This is what's revealed when the back of the unit is removed. Most of the space is occupied by the hard drive and the battery. The PCBs on the left are partly covered by a thin blue film of insulator.
Here’s a close-up showing the connections that need to be shorted. You need to gently peel back the blue film, then use a paperclip or similar to short out the two soldered joints (black and red wires) at bottom right.
After that, the device starts accepting charge again. A couple of hours later, the battery was fully charged and I was ready to go.
This problem seems quite widespread and I saw several instances in discussion forums around the web. It does appear to be a significantly bonkers design flaw. Still, now I know what to do!