Troubleshoot: iPhone 6 Home button return function failure

We received an iPhone 6 to repair, the prblem of this iPhone is the home botton doesn't implement the return function effect, which means the iPhone home button not working.  We need to fix it!

After checking, we've ruled out external issues, we excluded the peripheral accessories issues and decided the problem is on the iPhone motherboard.

Use multimeter to measure whether the iPhone motherboard fingerprint socket J2118#3 pin has resistance, the data is normal. When measure the voltage, we found the BUTTON_TO_AP_MENU_KEY_L_CONN only has 0.6V, it is obviously been pulled down, the normal voltage is around 1.3V. You can check those pins on phone circuit diagram.

R0313 starts with 392K, now we change it to 10K resistance, and then measure it again, we found the voltage reached 1.4V, almost normal. So we assemble the iPhone and test it, we found it's still no return function after we install the fingerprint button. However, when we use tweezers to press the J2118#3 pin ground, it can return. We suspect it is a fingerprint key problem.

After measuring, we found there is a 20K current limiting resistance on the BUTTON_TO_AP_MENU_KEY_L_CONN of fingerprint key. Decisively remove that resistor, and then use the phone soldering station to directly short connect them. 

After finish the above steps, use phone screwdrivers to install the iPhone, power on it,  enter the IOS system,  and test the home button return function, not it works perfectly.

Excellent solution for iPhone 6S home button not working

Customer sent an iPhone 6S to us, the fault phenomenon is that the iPhone home button is not sensitive and fail frequently. Get into IOS system to test it, the fingerprint function is normal. Sometimes the iPhone home button needs to be pressed several times before it can respond; we suspect there's a problem with the shrapnel button behind the fingerprint key.

Disassemble the iPhone by phone opening tools, then replace the fingerprint button and test it, now the home button function back to normal, so we exclude the iPhone motherboard error. Remove the waterproof adhesive covered by the shrapnel button, which is behind the fingerprint button. Put the multimeter on the corresponding pins, press the switch and test it, the data is normal, so we can eliminate the problem of the switch itself.

Put it under the phone repari microscope and observe it carefully, we found a rift in the edge of the line, pry the iron sheet off the power button, scrape the line, we can make sure it is disconnected. Solder the jump wire with phone rework station, this fault is resolved.

Before we pry the iron sheet, we need to clean up the solder tin in the red circle first by suction tin wire. If you don't clean it up, and directly pry it, it's easy to break the line again. Scrape the line with a sharp blade and gently scrape it, because the line is very thin, the blunt blade is easy to scrape off the line.

After the scrape, solder the tin on the pins. Find a thin copper wire and apply the tin, and then align them, heating the copper wire, finally you can fix it.

After soldering the jump wire, paint some green UV oil on it, fixed it with a UV lamp light, and then install the iron sheet in the same place. Welding the solder tin on the corner to fix it, and apply green UV oil to the edge position to fix the iron sheet.