DS damage faq

Hi guys!
I've got a hardware question. What part of ds is responsible for that kind of damage - on top screen only grey colour sometimes is changing/flashing to pink, when case is squized buzzed noise appear, and ds hangs, only grey to pink flashing is active. Here's example - http://www.youtube.com/watch?v=ut9HLwfZaXs

the electrical connections between the lcd pixel line drivers and the pixels themselves. The LCD glass itself could be cracked (not fixable). The other thing would be the connection wires that go through the hinge from the bottom of the unit to the top (probably fixable, if it's a ribbon cable or set of wires).

Maybe it looks like lcd damage, but It doesn't make sense. So why it hangs when bottom part(with mainboard) is squeezed and that never happen when I squeez top part of case (top screen), bottom screen is ok. I reconected ribbon wires to the mainboard. Nothing changed. Another thing - on the mainboard are lot of sings of permament black marker. Probably that mainboard was repaired. OK, I'll give up until get some other mainboard.

The black marker is typically a sign that the board was "ok'd" in factory. I've seen a couple ds boards and they all that.