Judging from the location on the board and the marking H2, it's a Zener diode, to protect the 12 volt rail from overvoltage. The value would be something a little above 12 volts.
I'm not quite sure about the package. Maybe SOD-323 or SOD-523.
Marking code of 470C makes sense for this part, looks like it could be an ELKE470FA with a 100 MHz cutoff frequency, a 47 pF cap, and a "C" month code.
Best Answer
SANYO 2SD1048. http://www.datasheetcatalog.com/datasheets_pdf/2/S/B/8/2SB815.shtml
It’s an PNP “audio” transistor. 20 V and 0.7 A rated.
Given the 0.7 A rating which is a bit more than small signal standard, was it located close to the speaker/headphones output?
X denotes 2SD1048. 7 denotes a hFE between 300 and 600.
You can most probably replace it with any PNP with similar hFE and current capability.