We check Youtube for the possible video tutorial on "how to disassemble the Samsung A7" but unfortunately there wasn't anything yet on the website. We already check the whole device tried to open the back part first but seems it's doesn't suit. We watched the teardown of other Samsung smartphone like Samsung S6, S6 Edge, Note 4 and Note 4 Edge none aren't similar to what is the Samsung A7.
Fortunately, Samsung A5 has teardown video on Youtube. We get to conclusion that Samsung A5 and Samsung A7 have the same way of dismantling. Well, every effort is worth a try. My friend Rjem finally opened the case, cleaned it and bring back Samsung A7 functionality.
Samsung A7 Disassemble Guide by Rjem