I am making a mobile display to run off of a 5-volt battery pack, and I was absolutely thrilled to find your post, as the TFT LCD monitor pictured is the exact model that I have. I've never hacked into such a thing before, and I have a couple of questions that will likely seem trivial to anyone with experience doing this kind of thing:
(1) Your post indicates completely removing the XL1509 black component. I'm assuming I just melt the solder on the 8 legs and pull it off the board. Do I need to replace this area with anything to complete the electric circuit, or does the circuit just (somehow) bypass this area when the XL1509 component is not there?
(2) Just below the XL1509 on the board is a little grey/white plastic mini-connector with a black and red wire coming from the "+","-","Menu" buttons on the backside of the monitor. After the modification, do I just plug that mini-connector with the black/red wires back in, or are these 2 wires the ones that get attached to the area in the lower middle of the board indicated in your picture?
(3) Just below the black/red mini connector is a larger mini-connector (the plastic thing in the lower right corner of the board), where the red,black,yellow, and white wires enter from the external wiring cable. After the modification, do I just plug that mini-connector with these 4 wires back in, or do the yellow/white get plugged in there but the red/black wires get moved to the area in the lower middle of the board indicated in your picture?
(4) Speaking of that area in the lower middle part of the board indicated in your picture where the 5 volt black/red wires should go: Do I just solder them into those holes or is there a more elegant/correct way of "wiring" them to that position?
In summary: I'm not sure which set of black/red wires get moved to that new lower/mid-board position (from the red/black wires in the smaller or from the larger mini-connector?), I don't know if I need to add any straight wiring to the board to "complete the circuit" after the XL1509 component is removed, and I don't know if soldering the red/black wires to the new lower/mid location of the board is the correct way to attach them to that new position. Thanks in advance for any advice/help!