Applying Low Voltage After Every Repair (Retina MacBook 2015 Only)

Written By: Jeff Suovanen
  • Comments: 21
Applying Low Voltage After Every Repair (Retina MacBook 2015 Only)

Difficulty

Very easy

Steps

2

Time Required

1 - 15 minutes

Introduction

The first-generation 12" Retina MacBook has a design quirk that requires connection to low-voltage power after a repair. If this step is skipped, permanent logic board damage may result. This procedure is not required for 2016 and later models.

Connecting the Retina MacBook to low-voltage power requires a 5-Watt A/C adapter (like the kind that comes with iPhones) and a USB-A to USB-C cable, neither of which is included in the MacBook's original box.

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    • Using a USB-A to USB-C cable, connect your MacBook to a standard 5 W iPhone wall charger.

    Just posting a comment to reinforce the fact that applying the low voltage power is necessary. Don’t skip doing it or you may ruin your (probably expensive) replacement logic board!

    David Manley -

    I applied higher voltage for a short period of time, maybe 3 minutes. Is the damage instantaneous? Have i trashed my logic board?

    Emmett Verhoog -

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    • Plug the charger into a surge-protected A/C outlet.

    • Wait until you hear the power connect chime (you should also see the battery charge symbol onscreen).

    • You'll typically hear the chime in 10 seconds or less—unless your battery charge level is very low, in which case it may take up to 15 minutes.

    • Power on your MacBook by pressing the power button.

    • Once the MacBook successfully powers on, you can disconnect the 5 W charger, and use/charge your MacBook normally.

    • If the MacBook fails to power on after 15 minutes, there may be an issue with your repair.

    This is quite scary. I wonder what the technical explanation for this behaviour is?

    Is it safe to just power it up using the built in battery? And then once it powers up, plug in the normal charger?

    Cool_Breeze -

    Is this necessary for the MacBook Pro (Retina, 15-inch, Mid 2015) 2,2 GHz Quad-Core Intel Core i7

    Where do I plug the usb c cable ? I can’t see any suitable port

    sissi -

    Is it necessary to use an iPhone charger, or can e.g. a 5W Samsung charger work?

    Ólafur Jón Thoroddsen -

    @cool_breeze applying 5v from USB is required to "jump start" this model or else it will not power back on. Essentially there is a battery cut out that requires external power to re-engage it.

    @sissi this step is only required for macbooks (not MacBook Pro). MacBook Pros do not have any such step needed to power back on

    @olafurt Yes any 5w charger will work. All that is required is 5v, 1A USB power using a USB a to USB C cable.

    Alex Garnham -

    This article's description should be revised to clarify that it does NOT apply to MacBook Pro models.

    andybaird -

    It can take longer than 15 mins to restart. My battery was completely flat and it took about 45 mins before the MacBook showed any signs of life.

    Shayne Riches -

Conclusion

To reassemble your device, follow these instructions in reverse order.

Author

Jeff Suovanen

Member since: 06/08/13

406751 Reputation

13 comments

I recently did an upper disassembly on my MacBook 2015 and was doing the steps for a low voltage power up but when I plugged the power in the MacBook made the startup noise for a second then restart and did it again in these short cycles. I’m wondering if I improperly did the start-up process or perhaps something else is going on?

John Wiedemer -

Hi John, I have the same problem, have you found a solution ?

maxime.duret -

What sort of logic board damage might happen if this step is not followed? One of our customers brought us his 2015 MacBook after attempting to replace the battery himself. The new battery is not recognized, and the computer shuts off after about a minute even when plugged in. Could this be the result of him not applying the low voltage power?

clover -

Did a batter replacement and woops… used a 10W supply for 15 minutes.

Then noticed my mistake and changed to 5W supply, but computer does not start at all.

Could this be the “logic board damage” mentioned?

Niels Koldsø -

I just replaced a new battery on my MacBook ProRetina Pro early 2015 and bought this cable and adapter after following all the steps and instructions but when I plug the cable in, the display screen is still off (black) no chime sound of battery charging symbol on the screen. I plugged everything back in correctly and followed the steps exactly how they said and my mac won’t display anything. What could be wrong?

Ervin Valdez -

hello, after battery replacement, I followed the low voltage start up however I got repeated chime noises on boot with a blank screen. I have yet to attach the adapter that came with it. It is a early 2015 model. Any help would be great.

roohi vad -

A year has passed, did you get an answer..?

Mike A -

Is a 2.5 Watt charger sufficient to get the job done, or will the laptop not turn on at all?

Stefanie Sulzer -

Does this step apply to the MacBook Pro (Retina, 15-inch, Mid 2015) A1398 ?

I wanna replace the trackpad, but mac doesn’t have a USB c port, should I use some sort of adapter or just skip the step?

Please reply

sissi -

You are fine, this step only applies to the 12" Retina MacBook from the same year as your MacBook Pro.

Aydan -

Chime, chime, chime and nothing else… 30 minutes and counting. I painstakingly followed the removal and replacement directions and now the computer will not fire up with the iPhone charger as directed. With my old, completely dead battery it would at least start up before if I kept the computer plugged in. It is a 2015 model.

Has anyone received any answers beside there may have been a problem with the install? “If the MacBook fails to power on after 15 minutes, there may be an issue with your repair.”

Is there another procedure to follow?

Mike A -

Seems no-one is getting any answers so I’ll just post my experience. I foolishly didn’t visit this site first so at first I had used the standard USB-C Charger and battery wasn’t recognised but mac booted with no chime but didn’t recognise battery. I put old battery back in and whilst it still said service battery it was at least seen. At this stage keyboard and trackpad wasn’t working but power button wasn’t. I then came about this article but only had a 10W charger available. The mac continued to boot off the original battery with no KB/Trackpad. I conceded and re-seated all cables again and fully closed lid and put screws back in. Then the keyboard and Trackpad worked. Just had no sound. So either the case has relevance or this time i re-seated the TP cable correctly. If that’s the case, I’m hoping the audio/headphones jack cable just needs re-seating which I will re-attempt when the next replacement battery arrives.

cameronpenna -

Does anyone know exactly which 2015 Retina MacBook models this applies to? All of them? I'm applying 5W to mine after repair and not getting a chime.

R McP -