As far as the 'whistling' goes, look around the DC-DC converter that does the USB 5v to 3v, U1. Could be that Inductor is going bad, it has some other iffy part or it's getting loaded down wrong.
No AN+ to LSY = full Up movement.
No GND to LSY = full Down movement.
No AN+ to LSX = full Left movement.
No GND to LSX = full Right movement.
Make sure both POTs have the AN+ (1.8v) and ground they need. AN+ is on TP103 there. Also make sure none of your jumper wires are touching each other or any other solder joints in there.
Hi. Replaced left analog stick and I have full right movement. No small missing smd components around. Checked voltages, I have on both pots 1.8v and gnd. If pressing L3 will move slightly to opposite side. Disconnetting the pot will return to the center and the up/down pot will work fine but of course no left/right movement. what to check next? Can you help?
EDIT: Sometimes It's not full right movement, in gamepad tester I can see it's behaving like there is drifting.
EDIT 2: Checked R42, 100 ohm.