How To Fix iPhone 8 With No Touch

How To Fix iPhone 8 With No Touch
Device	IPhone 8, IPhone 8 Plus
Affects part(s)	Main Logic Board
Needs equipment	Soldering Iron, Hot Air Station, Microscope
Difficulty	◉◉◉◌ Hard
Type	BGA, Soldering

Problem description

How to fix an iPhone 8 that turns on, but there's no touch. It will not detected you touching the screen. Home button works, but no touch function on the display.

(Figure 1) -- How to fix no touch on iPhone 8. Bend out the pins

Symptoms

• No Touch
• Even with new screen, still no touch

Solution

Diode mode the LCD connector (J5700) and check for any lines that are OL or 0.000 V (shorted). In most cases, you'll find pry damage near the connector, causing damage to a filter or resistor. Commonly damaged:

• FL5776
• FL5762
• RR5772

If you find an abnormal diode mode value, see if the name of the line mentions the word "touch. This will help assure you that you're looking at the right spot

Follow the path of the abnormal value by doing diode mode readings on every component in the path, to see where the correct diode mode reading is located. That will point you towards the failed component.

For example, if the top side of FL5776 gives you OL, but the bottom side of it gives you 0.442, then you found your failed component.

Another solution:

If you found the diode mode readings are all normal, then most likely it's a connector issue

Find the 4 ground pins on the LCD and Home Button connectors and use fine tip tweezers or an Xacto blade to bend them outwards.

Refer to Figure 1.

Pull these corner ground pins outwards to fix no touch

Usually this issue is caused from too many screens being unplugged and plugged in, causing those pins to be pushed outwards

Or from someone plugging in a 8/8P screen into a 7/7P board or vice versa

If still no touch, you can try replacing the LCD connector to see if that solves it.