OT: greenish area in new monitor

[Ralf Mardorf]

From my experiences with CRT monitors and broken VGA cables, the whole
screen is missing a colour. Nowadays I'm using a LCD display connectedby
a HDMI cable and I neither didn't experience a cable or connector
related issue, nor a broken semiconductor. I suspect that if a HDMI
cable should be broken and/or a connection should be fishy, neither the
whole screen is missing a colour, let alone that a part of the screen
is missing a colour. IMO the OP should take a look at a forum that
focus on repairing equipment.
Very seldom the cable or a connection caused issues, if one of my CRT
monitors failed, most often I needed just to resolder some soldering
joints on the CRT's PCBs, very seldom I needed to replace
semiconductors.
I've got some experiences with issues of CRTs and repairing CRTs, but
no experiences with LCDs, since my LCD monitor isn't old.

IMO guessing, without experiences is wasting time. Either ask a friend
who has got experiences with broken LCDs and repairing those LCDs or
join a forum that is aimed for sharing experiences with repairing gear.