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Model A1502 / 2.4, 2.6, or 2.8 GHz dual-core Intel processor / Released October 2013

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No display, backlight and external display works

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.

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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.

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I have some experience repairing iPhone motherboards, replacing chips etc. But I never did MacBooks before. It could indeed be a SMC problem, but the laptop does work fine when LVDS is disconnected. Also in the Apple Diagnostics thing it just says "Battery not detected", nothing about SMC.

Is there a way I can test to make sure it's the SMC causing the problems?

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Diagnostics doesn't get that deep into failures..never heard it gives back an SMC malfunction error. The only way I know of, is to get into schematics and verify pin by pin that every power and data line is working as it should until you find the faulty one.

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Depending on the diagnostic software it can give you a good clue is SMC is working or not. The newer built-in diagnostics is useless for much of anything.

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It can give an SMC error, but idk when it does that. But I'm pretty sure it's indeed the SMC that's gone faulty. I've to find out what's the best option now, programmed SMC's are pretty hard to find.

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You'll have to find the a faulty board with same board number for spares to get a suitable SMC, you won't find anywhere a new one unfortunately.

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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.

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But that isn't the only thing that's happening. Also the battery isn't detected, which points to the SMC. Plus the SMC regulates the power states of the backlight of the display and all that kind of stuff, so it still could be the SMC. Also on the back side of the keyboard, under the motherboard, there are some signs of waterdanige. You can clearly see the SMC had been wet before, and some stuff around it but no other ICs really. No corrosion or burned looking stuff on the motherboard though.

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I look at it as the SMC being the end of the line and ultimately , sure it could be possible, but I'd test the components way before that.

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Yes, I'll do some more testing with the microscope when I have some more time this week.

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Good and klet us know what you find. Have you determined what board this is? 820-3476-A or 820-3536-B?

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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

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No, it definitely not anything with the battery or magsafe circuitry. I'm almost 100% sure it's the SMC. Also the macbook doesn't work on battery since it's not even detected and completely empty and not charging.

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Roan de Graaf will be eternally grateful.
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