Chosen Solution
I’ve got a MacBook with some weird problems. When I just start it up only with the charger connected I hear the Chime, it starts to boot and when it gets to the end of it’s booting sequence the backlight turns on and that’s it. No image on the display. When I connect an external monitor via HDMI and boot the laptop it Chimes, shows the Apple logo on the external display and get’s stuck on a black screen afterwards. When I boot the laptop with the lid closed with an external monitor connected it boots fine and works, unitl I open the lid. Then it just get’s stuck and I can only move the cursor. When I disconnect the LVDS cable of the internal display and boot with external monitor connected, it works totally fine and I can use the laptop normally. This is all I’ve found out so far. The LVDS connector itself looks fine, but it could be faulty. It seems like it’s shorting out something when connected but I don’t know where to look. It is possible the MacBook had waterdamage, but there are no signs of any corrosion or something. The waterindicator on the battery control board is red though. Battery also isn’t detected on this macbook but I guess that’s another story.
Battery not charging and weird behaviour with lid open/closed, together with signs of liquid damage, point straight to the SMC that is involved in both processes. Liquid has probably shorted something involving SMC and/or the chip itself. It sounds like a serious issue that needs professional care, not much you can do without the work of a Pro here.
Roan de Graaf this alone “disconnect the LVDS cable of the internal display and boot with external monitor connected, it works totally fine and I can use the laptop normally” makes me doubt that this is an SMC error since it works under those circumstances, or for as long as the lid ics closed. The error is most likely on the circuitry that close when you open the lid to display the video to your MBP. I would suggest that you post some really good images of your logic board with your question. Both side and review the chematics to identify the components related to that. Let us know if you board is a 820-3476-A or 820-3536-B so we can assist you a bit more with this.
Sounds like a bad battery and/or MagSafe adapter/DC In board here as the SMC settings are getting lost. Run CoconutBattery with the system plugged in and again with it on battery alone. Post both here for us to see Adding images to an existing question
