23 November 2018

iPhone Battery Drain and Consumption Test | Logic Board drain

How to check iPhone motherboard drain battery issue?

  • iPhone leaking power quick
  • Consume or drain the battery fast
  • New battery same problem
  • Restore the firmware and still the same

A lot of shops claim they know how to repair motherboard, they really don't do well. Most of them send to another shop to do or they just blindly change whatever IC that is related to power, after they messed a lot of things, then they return it with the same problem plus wasted few weeks of time. If you have an iPhone that having drain or consumed battery power fast. The first thing we suspect is the battery, but what if the problem still exists after you replaced a new battery?

Today I'm going to teach you how the professional to check the iPhone logic board drain problem.

(I uploaded a Cantonese video into YouTube. English subtitle provided)  - YouTube Link

It's best you read the entire article instead of just watching the video above link.
Especially for beginners who want to learn repair logic board of iPhone.

Tools require:

DC power supply 
iPhone power cable

How to check iPhone logic board drain battery problem

1st diagnosis method

Unplug everything, including battery, LCD and all flex that connected to motherboard. Except for the power button flex which you will need it. (We can click the power button without the flex, but I'll skip this tutorial)

Next step is to connect it to the Power Supply.
The power supply can read how much is your iPhone drawing the power.

Make sure to set the Power Supply's current to 1A or lower.

We must slowly turn the knob that giving power voltage into the iPhone. By watching the meter of Amperage we can know is the iPhone draining the power before we power the iPhone on. 
Slowly raising the voltage until the battery level which is around 3.7v.

It should be staying in ZERO and NOT drawing any power before we switch the iPhone ON. 

My power supply's left gauge is Amperage meter. We look at the lower line because I already locked it into 1A.
In this case, the red needle stoped at 0.2A.
This means the iPhone is leaking 20ma before we power it on.
This is an iPhone 5S that having a battery drain quick problem. Even we switch the iPhone off, it will still consume the battery very fast.

Can it be fixed?
Yes, but that's not today's topic.

What if the scenario above is not happening? 

If above is acting normal then we do the second step of diagnosis - BOOT-UP TEST.

2nd Diagnosis: Boot-Up Power Test

What is boot-up power test?

Boot-up-test can tell is the motherboard only drawing the power more than normal after turned on.

How to do Boot-up test:

Hit the Power Button once. Not to turn it on. Just once. The iPhone will be turn on if you holding the button more than one second.

But if we just lightly press it once, it will do a self-power testing.

When we just lightly click once on the power button, a normal iPhone would respond from 0 into 80mA and then drop back into 0.

A charging IC problem can be easily detected by this method too. 

This is a digital power supply. The function is the same. It can be more accurate for some advanced diagnoses that I won't teach it here.
As you can see in the photo above, this iPhone 7 booting-test at 218ma which is very high.
This indicates there is a component in the logic board drawing a lot of power. (Motherboard problem)

Maximum of iPhone comsumption is 1A.  (1A= 1000mA)
But iPhone never constantly running 1A.

So far there is no app that would constantly running your iPhone at full speed.
Only If CPU is doing a full speed benchmark test. 

By the way, this iPhone 7 boot-up started at 200ma.
This means it's already consuming 200mA when it's turned on.
I'm sure this iPhone 7 at least needs to 3 times a day.

Can it be fixed?
 If we are first hand to repair the motherboard, it will be a quick JOB which can be fixed within a day

What if the above two scenarios are not happening?

Then the problem is coming from one of the flex, LCD or camera.
Connect all the flex back except the battery then do methods above and you'll found out is the external problem which is not a logic board issue.
Easy money. Screw-drivers job, no need micro soldering.

We received countless of failed repair iPhone from another shop. They mess up a lot of things which they shouldn't touch. They changed things without proper training/educated.
The worst matter is the workmanship quality, they usually did more damage on the board. In the end, we repaired it at a higher cost and a longer time needed to find the original problem...