I'm about to repair a Medion S9714 tablet pc which was showing strange battery drain even if shut down completely, a lot of heat dissipation when working or charging and the backlight not reaching full brightness.
I narrowed the problem down to a tiny boost converter that's always getting quite hot, even if the tablet is shut down and the backlight / TFT is off. I guess the converter chip itself is faulty, maybe as the result of a defective inductor (will have to check that). The problem is, the semiconductor is enclosed in a tiny DFN-8 package (2*2mm² footprint) that only carries the designation "7212" and in the second line "8". I attached a few pictures with a photo of the corresponding PCB section, a schematic (as transscribed from the PCB) and two thermal images of the section and the complete board with only the battery plugged in an nothing else started/energized - clearly observable, the only heat source is the mentioned chip (some apparent heat sources are reflections on the RF shielding cans). Has anybody got a clue what semiconductor this is? I tried comparing the major manufacturers' stuff but didn't find a matching pinout so far. Thanks for the help!
Cheers,
Thomas