Nintendo Switch Lite No Backlight: Difference between revisions

Nintendo Switch Lite No Backlight
Device	Nintendo Switch Lite
Affects part(s)	Motherboard
Needs equipment	Microscope, Soldering iron, multimeter
Difficulty	◉◉◉◌ Hard
Type	Soldering

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Latest revision as of 14:14, 24 August 2025

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Problem description

The device turns on but the image is really hard to see

Symptoms

The Backlight is not working

Solution

This can be caused by a faulty display or a problem in the backlight circuit.

Diagnostic Steps

The first step is to always try new parts beforte assuming you have motherboard problem so start by testing a new display, Sub Board, Flex that connect the sub-baord to the motherboard.

If parts dont fix the issue the problem is with the backlight circuit.

Start by inspecting the Connector where the flex that comes from the sub-board to the main board for any liquid or physical damage.

If the FPC looks look we need to diagnose the backlight circuit.

The first step is check for shorts in these points, put your multimeter in continuity mode and prove the points in the image bellow these points cant have continuty to ground, if they do there is a short circuit.

If there is no shorts next step is check voltages, these voltages ony show up with the device turned on and they display plugged in.

The main voltages we need to check are:

3.6V this the VIN of the backlight Controller

1.8V is the enable signal that comes from the APU, measure this like you need to scrap the point on the board to be able to acess it.

17V is the expected output of a good working backlight circuit,if youhave 17V here the backlight circuit is working and should test parts again.

If 3.6V and 1.8V are ok try and replace the Backlight controller.

Repair Steps

Replace the FPC

The FPC is made of plastic so be careful with heat it is easy to melt it when soldering a new one.

This FPC can be found online easily.

Replacing the Backlight Controller (TPS61163)

Desoldering the Old Chip:

Cover the FPC with kapton take to avoid melting it.
Apply heat to the TPS61163 chip from above using a hot air station. Heat for several seconds until the factory solder begins to melt.
Gently nudge the chip with tweezers. If it moves, it’s ready to be lifted off.
While the board is still hot, use solder wick and a soldering iron to clean old solder from the motherboard pads.

Soldering the New Chip:

Align the new chip on the motherboard. Match the dot on the chip to the small triangle marker on the motherboard for correct orientation.
Heat the chip from above using a hot air station. Watch for the solder to melt, indicated by slight chip movement.
Gently touch the chip with tweezers to let surface tension settle it into place. Avoid excessive force.

Final Testing

Turn the console on and make sure the brightness works fine from minimum to maximum

@@ Line 1: / Line 1: @@
+{{Repair Guide
+|Device=Nintendo Switch Lite
+|Affects parts=Motherboard
+|Needs equipment=Microscope, Soldering iron, multimeter
+|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.
+ -->
-'''820-3662 NO NUMERIC KEYS / CAPS LOCK INVERTED / INPUT DELAY - TOUCHPAD ISSUES'''
+The device turns on but the image is really hard to see
+[[File:Switch Lite Backlight Circuit.jpg|thumb|482x482px|Components related to Backlight]]
-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).
+== Symptoms ==
+<!--
+Detail all measurable or observable symptoms in this section.
+-->
+* The Backlight is not working
-🔍 '''Step-by-Step Diagnosis'''
+== 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.
-Visual inspection: Corrosion was found near the keyboard/trackpad controller area (U4801).
+-->
-Voltage drop across R4814 (relevant resistor in the SPI circuit) was checked and confirmed expected values.
+This can be caused by a faulty display or a problem in the backlight circuit.
-'''''Chip replacement attempts:
+=== Diagnostic Steps ===
-'''
+The first step is to always try new parts beforte assuming you have motherboard problem so start by testing a new display, Sub Board, Flex that connect the sub-baord to the motherboard.
-'''First attempt:'''
+If parts dont fix the issue the problem is with the backlight circuit.
-Replaced U4801 with a donor chip from board 820-3476 (MacBook A1502).
+Start by inspecting the Connector where the flex that comes from the sub-board to the main board for any liquid or physical damage.
-🟡 Result: Keyboard worked, but Caps Lock LED was reversed (lit when lowercase, off when uppercase).
+If the FPC looks look we need to diagnose the backlight circuit.
-'''Second attempt:'''
+The first step is check for shorts in these points, put your multimeter in continuity mode and prove the points in the image bellow these points cant have continuty to ground, if they do there is a short circuit.
+[[File:Switch Lite Backlight circuit.png|center|thumb]]
+If there is no shorts next step is check voltages, these voltages ony show up with the device turned on and they display plugged in.
-Used a chip from MacBook A1278 (Unibody).
+The main voltages we need to check are:
-🔴 Result: Severe input delay, no trackpad and overall poor keyboard behavior.
+.6V this the VIN of the backlight Controller
-'''Final solution:'''
+.8V is the enable signal that comes from the APU, measure this like you need to scrap the point on the board to be able to acess it.
-Replaced with U5701 from donor board 820-3332.
+V is the expected output of a good working backlight circuit,if youhave 17V here the backlight circuit is working and should test parts again.
+[[File:Nintendo Switch Backlight Voltages.png|center|thumb|Nintendo Switch Backlight Voltages]]
-✅ Result: Keyboard fully functional, Caps Lock LED working properly, no delay, trackpad also fully operational.
+If 3.6V and 1.8V are ok try and replace the Backlight controller.
-'''⚙️ Technical Conclusion'''
+== Repair Steps ==
-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.).
+=== Replace the FPC ===
+The FPC is made of plastic so be careful with heat it is easy to melt it when soldering a new one.
-⚠️ '''Using an incompatible IC can cause:'''
+This FPC can be found online easily.
-Reversed Caps Lock LED logic.
+=== Replacing the Backlight Controller (TPS61163) ===
+Desoldering the Old Chip:
-Noticeable input delay on keys input.
+* Cover the FPC with kapton take to avoid melting it.
+* Apply heat to the TPS61163 chip from above using a hot air station. Heat for several seconds until the factory solder begins to melt.
+* Gently nudge the chip with tweezers. If it moves, it’s ready to be lifted off.
+* While the board is still hot, use solder wick and a soldering iron to clean old solder from the motherboard pads.
-Malfunctions with the trackpad or power button.
+Soldering the New Chip:
-✅ '''Key Takeaway'''
+* Align the new chip on the motherboard. Match the dot on the chip to the small triangle marker on the motherboard for correct orientation.
+* Heat the chip from above using a hot air station. Watch for the solder to melt, indicated by slight chip movement.
+* Gently touch the chip with tweezers to let surface tension settle it into place. Avoid excessive force.
-“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.”
+== Final Testing ==
-— Diógenes el Perro
+Turn the console on and make sure the brightness works fine from minimum to maximum
-🛠️ Note: Neither the BIOS nor the SMC were reprogrammed during this repair.