TS,
my DS had same issue as yours
bought it from a forumer here..confirmed refurbished set but he didnt declare it
i took it to the shop for fix, after fix 1 month..same issue appeared

first fix said motherboard and lcd issue...
2nd fix say 2 chipset rosak d
both fix cost alot, just advice the people here, do careful not to get refurbished set
good for you the barcode still can see, my barcode totally wiped off