man.. I had to TWICE.
I bought a DS and an R4 from this guy online. I didn't know any better back then. but now I know, the R4 was fake.
anyways, I played with the DS for a week, and then bam. It just turned off and wouldn't turn on again.
I had to replace it at nintendo (thank goodness it still had it's warranty)
then, 2 DAYS after i got it replaced, it turned off again and wouldn't turn on.
I then had to go replace it AGAIN
At this point I was thinking it was the R4's fault. So I got a cycloDS and never had the problem ever again.
although, to this day I still don't know what made my DS break... Many people told me it couldn't have been the R4..