I recently purchased a used Sansa Clip Plus from Amazon. It arrived yesterday, and I immediately installed Rockbox on it.
The problem was, the player didn't have much charge left in the battery, and I fear that it must have turned off before the operation could be completed properly. After the Clip lost power, I was unable to turn it on.
I plugged it in for a while and let it charge. Eventually, I was able to use a small paper clip to hit the reset button on the back of the player. This allowed it to turn on, and I was able to get it working.
I copied some music on to the internal storage and started experimenting with it. It appeared to work fine, and I explored the software while listening to hear the audio quality.
I have no idea if this is related, but I tried playing the Doom plugin and was unable to exit normally I had to reset the player. I'm not sure if that matters, but I figured I would include it.
This leads up to the current issue. I decided to charge the device until the battery was full. When I tried to use the device last night, it kept turning off a few seconds after I turned the player on. It doesn't matter what I do, the same thing happens. If I had to guess, I would say it takes about 5 seconds. It doesn't matter whether I am using the built in software or Rockbox. The same holds true for when I connect the player to my computer and try to copy files to it.
Oddly enough, if I constantly press the power button, the device will stay for a while longer. I have no idea why.
That's all the information I could think of. Please ask more if I have left something out. Any help would be greatly appreciated, especially because I'm not sure I can return it to Amazon because I tried to modify the software.