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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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Where is the SMC on the logic board? Cleaning after spill.

Question first:

Since the current problems I'm seeing SEEM to be related to the SMC, I want to pay special attention to that circuitry. Can someone point out where on the logic board that is?

I'm hoping a couple hours and a few dollars in cleaning supplies get it working again, but if not then I'll have to order a replacement board.

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Problem:

My Late 2013 13" Retina MBP had a mild coffee spill.

I turned it off immediately. Drained it as best I could. Opened the button. Then I didn't touch it for a couple of days.

Then I bought 4 pounds of silica gel dessicant crystals and put the MBP (wrapped in a towel) in a cooler with them. I left it there for 72 hours. The MBP was off for a total of a week.

I tried powering it on.

At first, everything seemed to go well. All the keyboard buttons worked. Trackpad worked. No issues. I plugged the charger in... It charged ok. It went from 19 to 28% while I used it.

Later in the day I came back to it and it wouldn't wake. I tried an SMC reset - no help. I came back a few hours later and tried to wake it and it came up. An hour or so later I shut it down just to see if it would come up. The power button did nothing. I tried a few combinations of attaching the charger, removing the charger, SMC resets. I got it to come on a few times but the boot up progress bar usually never made it past 50% before it shut down again. One time only did it make it to the login screen, but it shut down before I could log in.

Up until now the charger light would turn briefly green when attached and then go amber. But after this I got no indication from it.

I gave up and walked away. Twenty minutes later the MBP powered up spontaneously and shut down a few seconds after. This happened 4-5 times in an hour.

I walked back over to it and tried to power it on manually. It chimed and I saw the boot screen. The fan was loud and at 100%. It shut down before reaching the login screen.

I took the bottom cover off again and disconnected the battery. I haven't gone back to it in 2 days.

I did notice what appeared to be some light mineral deposits or corrosion on the DC in board.

I haven't had the logic board out yet to look at the other side. That's my next course of action.

I will clean it off with some 99.9% isopropyl and distilled water.

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Thanks!

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Sadly the approach you took did little to address the root issue of the coffee spill and in fact may have messed you up. It's the acids and other stuff in the drink that once dried can eat away at the circuitry and create short-circuits which can damage chips and other components.

Just for the record Silica gel or Rice will do little to address a spill. They do help when you are in a humid environment to absorb the moisture in the air within your case so it doesn't condense onto your system (or camera). So if you are hiking though a foggy rain forest it could help.

Next time pull the battery connection ASAP and leave it disconnected until you have fully cleaned the spill out completely using distilled water and cotton swabs to clean the areas you see which are wet then going over the same areas with a high grade isopropyl alcohol (85% or better). Sadly, you'll need to take the system apart as often the other side of the logic board gets wet when the spill is though the keyboard/track pad. If you can't clean things quickly keep the battery disconnected and keep the system as cool as you can as heat speeds up the corrosiveness of what ever you spill in the system and wipe down anything that you can.

OK, back to your question I doubt you could isolate the issue to the SMC part of the logic board as being the area that needs to be cleaned given the symptoms. It sounds more like the power logic is having problems here. The reason SMC reset appears to address the problem is SMC's last fail state was cleared so it startup reads the rails power then goes back to fail state. In fact your constant reset could do more harm here! As SMC is working trying to protect your system from more damage

So you'll need to strip the system down carefully cleaning the logic board as well as the other parts and hope cleaning it will resolve things. Otherwise its time for a new logic board.

One last concern here is the keyboard & trackpad, you may need to replace it as spills tend to kill them.

Good Luck!

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2 Comments:

Thanks for the reply Dan.

After opening the lower case I removed the heat sink, fan, logic board, DC in board, and IO board.

Every single one of them look perfect. I've worked with other people's spill damaged laptops before... Usually there is evidence. A film, some corrosion, flakes of sugar or some other substance. There is no evidence of evaporated liquid residue on either side of any of these components. I did see some slight corrosion on the DC-in-board, but nowhere else. I cleaned it off with 99.9% alcohol.

Is it possible that little spot of corrosion was the sole cause of my issues?

by

I doubt it, it's a good start though.

The main logic board power rails is what SMC is monitoring.

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