IPhone 6S No Image: Difference between revisions

IPhone 6S No Image
Device	IPhone 15 Pro Max
Affects part(s)	Motherboard
Needs equipment	Soldering Iron, Hot-Air Station, Microscope
Difficulty	◉◉◉◌ Hard
Type	Soldering

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Revision as of 17:39, 21 September 2025

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Problem description

The iPhone doesn't charge and touch doesn't work

Symptoms

Device doesn't charge.
Device doesn't charge and touch is also not working.

Solution

This problem is usually associated with a bad U9500 this chip detects what is connected in the USB C port.

Diagnostic Steps

The first step is to always rule out faulty parts. Start by testing a new display and battery.

If your device doesn't charge, this doesn't mean the U9500 is bad. This issue can also be caused by a faulty Tigris IC. A good way to test is to try a wireless charger. If the device charges with a wireless charger, it means the Tigris IC is working.

For the U9500 to work, it must have 5V on the pad below. To measure this, you will need to separate the motherboard, connect the charging port, and then connect it to a charger.

If you measure 5V at the input, it indicates that the U9500 is receiving power and should be functioning.

Repair Steps

The U9500 doesn't work alone, it functions in conjunction with a ROM IC (U9720). This creates a challenge because we cannot replace just the U9500. To replace the U9500, we must also replace the U9720, and both components need to be sourced from a donor board, specifically from an iPhone 15 Pro Max. They cannot be sourced from an iPhone 15 or 15 Pro.

Replacing the U9500 and U9720

Use your hot air station to desolder the old U9500 IC from the motherboard, while its still hot desolder the ROM IC U1030.
Clean the pads on the motherboard thoroughly.
Reball the new U9500 if it isn't pre-balled.
Reball the new U9720.
Use your hot air station to solder the new U9500 IC onto the motherboard.
Solder the new U9720

After replacing the U9500 and U9720, test if the phone is charging and if the touch functionality is working. To do this, connect the charging port, screen, and battery to the top board. The iPhone 15 Pro Max can power on with just the top board. Plug the phone into a charger and use an amp meter to measure the current the phone is receiving.

After confirming that the phone is charging and the touch functionality is working as expected, the next steps are to reball the bottom board and resolder both boards back together.

Final Testing

After assembling the phone, ensure every function is working as expected, not just the charging circuit.

Connect the phone to a fast charger and check if it fast charges using an amp meter. If it’s fast charging, it should draw 9V and around 2+ amps, depending on the battery capacity.

Connect the phone to a computer and verify that data transfer is working.

Connect USB-C headphones and confirm that audio is functioning as expected.

@@ Line 1: / Line 1: @@
-'''820-3662 NO NUMERIC KEYS / CAPS LOCK INVERTED / INPUT DELAY - TOUCHPAD ISSUES'''
+{{Repair Guide
+|Device=IPhone 15 Pro Max
+|Affects parts=Motherboard
+|Needs equipment=Soldering Iron, Hot-Air Station, Microscope
+|Type=Soldering
+|Difficulty=3. Hard
+}}
+{{stub}}
+== Problem description ==
+<!--
+Provide a concise description of the issue here. Be  as specific as possible to help readers quickly determine whether or not this is the exact problem they are facing.
+ -->
-The device arrived with the numeric keys on the internal keyboard non‐functional, despite a complete keyboard replacement. Visible moisture and sulfation were detected near the keyboard’s SPI controller (U4801).
+The iPhone doesn't charge and touch doesn't work
+[[File:Iphone 15 pro max not charging.jpg|thumb|iPhone 15 Pro Max Not Charging.(Image by Cell Phone Repair Academy)]]
-🔍 '''Step-by-Step Diagnosis'''
+== Symptoms ==
+<!--
+Detail all measurable or observable symptoms in this section.
+-->
+* Device doesn't charge.
+* Device doesn't charge and touch is also not working.
-Visual inspection: Corrosion was found near the keyboard/trackpad controller area (U4801).
+== Solution ==
+<!--
+If the issue has a single, specific solution, provide it in this section and delete the sub-headers below. Otherwise, if there are multiple potential causes for the problem, outline the process of identifying the root cause and offer corresponding solutions below.
-Voltage drop across R4814 (relevant resistor in the SPI circuit) was checked and confirmed expected values.
+-->
-'''''Chip replacement attempts:
+This problem is usually associated with a bad U9500 this chip detects what is connected in the USB C port.
-'''
-'''First attempt:'''
+=== Diagnostic Steps ===
+The first step is to always rule out faulty parts. Start by testing a new display and battery.
-Replaced U4801 with a donor chip from board 820-3476 (MacBook A1502).
+If your device doesn't charge, this doesn't mean the U9500 is bad. This issue can also be caused by a faulty Tigris IC. A good way to test is to try a wireless charger. If the device charges with a wireless charger, it means the Tigris IC is working.
-🟡 Result: Keyboard worked, but Caps Lock LED was reversed (lit when lowercase, off when uppercase).
+For the U9500 to work, it must have 5V on the pad below. To measure this, you will need to separate the motherboard, connect the charging port, and then connect it to a charger.
+[[File:5V U9500 input.png|center|thumb|U9500 5V Input]]
+If you measure 5V at the input, it indicates that the U9500 is receiving power and should be functioning.
-'''Second attempt:'''
+=== Repair Steps ===
+The U9500 doesn't work alone, it functions in conjunction with a ROM IC (U9720). This creates a challenge because we cannot replace just the U9500. To replace the U9500, we must also replace the U9720, and both components need to be sourced from a donor board, specifically from an iPhone 15 Pro Max. '''They cannot be sourced from an iPhone 15 or 15 Pro.'''
-Used a chip from MacBook A1278 (Unibody).
+[[File:IPhone 15 Pro Max.png|center|thumb|IPhone 15 Pro Max Charging ICs]]
-🔴 Result: Severe input delay, no trackpad and overall poor keyboard behavior.
+==== Replacing the U9500 and U9720 ====
-'''Final solution:'''
+* Use your hot air station to desolder the old U9500 IC from the motherboard, while its still hot desolder the ROM IC U1030.
+* Clean the pads on the motherboard thoroughly.
+* Reball the new U9500 if it isn't pre-balled.
+* Reball the new U9720.
+* Use your hot air station to solder the new U9500 IC onto the motherboard.
+* Solder the new U9720
-Replaced with U5701 from donor board 820-3332.
+After replacing the U9500 and U9720, test if the phone is charging and if the touch functionality is working. To do this, connect the charging port, screen, and battery to the top board. The iPhone 15 Pro Max can power on with just the top board. Plug the phone into a charger and use an amp meter to measure the current the phone is receiving.
-✅ Result: Keyboard fully functional, Caps Lock LED working properly, no delay, trackpad also fully operational.
+After confirming that the phone is charging and the touch functionality is working as expected, the next steps are to reball the bottom board and resolder both boards back together.
+== Final Testing ==
+After assembling the phone, ensure every function is working as expected, not just the charging circuit.
-'''⚙️ Technical Conclusion'''
+Connect the phone to a fast charger and check if it fast charges using an amp meter. If it’s fast charging, it should draw 9V and around 2+ amps, depending on the battery capacity.
-The U4801/U5701 keyboard SPI controller contains firmware/configuration specific to each board model. These chips are not freely interchangeable between different MacBook series (A1278, A1502, A1398, etc.).
+Connect the phone to a computer and verify that data transfer is working.
-⚠️ '''Using an incompatible IC can cause:'''
+Connect USB-C headphones and confirm that audio is functioning as expected.
-Reversed Caps Lock LED logic.
-Noticeable input delay on keys input.
-Malfunctions with the trackpad or power button.
-✅ '''Key Takeaway'''
-“The keyboard IC (U4801/U5701) must come from a firmware-compatible logic board. Although they are electrically identical, their internal configuration depends on the board model and its interaction with the SMC.”
-— Diógenes el Perro
-🛠️ Note: Neither the BIOS nor the SMC were reprogrammed during this repair.