this macbook pro had a massive short to ground due to liquid damage. it’s the worst i have ever seen. the electrical current sizzled so long it carbonized multiple layers deep into this motherboard.

this machine was a 15″ macbook pro touchbar a1990 emc 3215. the motheboard was 820-01041-a.

there was data on this computer that needed saving and the only solution was to get this computer running again. this version did not have storage that we could access unless the computer was revived.

first inspection revealed some liquid around the trackpad cable.

i removed the retaining bracket for the 2 connectors underneath. the trackpad connector looked fine, but i pulled up the nearby keyboard connector (j6700), and it looked ugly. really ugly.

they keyboard cable is replaceable 821-01664-a, so i focused on the motherboard side of the connector. lets get that removed and see what i have to work on. and it looked really really bad.

pin 23 got absolutely sizzled and the line pp5v_g3s was shorted to ground. it had connected to the ground pins located on either side (pins 21, 25). as a result the motherboard had carbonized. it had turned to a crumbly charcoal. gently dug out and removed the carbon leaving the crater you see below.

unfortunately, pp5v_g3s was still shorted. nothing else on the board looked suspect, so the next thing to do was to inject some voltage into that line and see what heats up.

i found a good place on a capactor (c7607) down the line a bit and began the process. absolutely nothing seemed to heat up anywhere else on the board. the only warming i got was around the j6700 connector from the crater area.

i began to suspect that the short may be coming from deeper in the crater. so i began to dig further. yikes… i was taking a gamble, but all my knowledge pointed to this being the solution. i removed the power supply from my lines that i had used to inject voltage and hooked them up to my multimeter in continuity mode. the one that has an audible beep if there is continuity (short). kind of annoying to have a constant beep, while digging deeper into this already giant hole on this motherboard. i cringed as i was scraping through the multiple layers. each scrape left me questioning my decision on whether or not this was the correct path. BEEEEEEEEPPPPPPPP, scrape, still beeeeeeeepppp.

as i slowly dug deeper and deeper the beeping abruptly stopped! i had carved out the short! whew!!!

but at what expense??? this board was a multilayer board and was possible that other lines were criss crossing where i had been digging. and possible that i had severed something by attempting to relieve this short. but there really was no other choice. the damage had been done and my attempts could only bring us closer to a solution. we would have to move forward to see.

this crater was massive. you can see the many copper layers of this motherboard. the heat from my attempts to locate the short were quickly absorbed into this large cooper heat sink. it’s no wonder i was not able to see a specific heat point. the carving had dug into the nearby pads which were ground pads. and the next step was to begin the rebuilding process, and fill this crater and isolate/protect the exposed copper ground layers.

i had another donor board, so i pulled the connector off and transplanted it to our problem board and began to rebuild the missing traces and connect them to nearby alternate points along their respective lines. the main power rail pp5v_g3s i tied to nearby l6700 at pin 2. it was a bit of a run, but the closest that made sense.

the cable arrived and it was time to see if all this work would pay off. i reassembled the computer and pressed the power button…

…and it began to show normal life signs!!!

and it booted!!!

and charged!

the computer was running as it should and had been fully repaired!

i did advise the customer to immediately preserve their data as if the computer could quit at any moment, but that this computer would more than likely run like normal for years to come.

i always breathe a sigh of relief when a device that i have been working on comes back to life. it’s very rewarding. sure there is some risk, but i try to triage ones that seem beyond hope and avoid unhappy situations, but i also seem to have some great success with devices seemingly beyond hope. i’m glad this turned out to be a win.

thanks for looking over my shoulder with this repair journey. hope you enjoyed the ride.