[SOLVED] I'm looking for YOUME Y368 repair guide or schematics (free) - Phones & Tablets Forum

Hi,

I'm hoping you can help me out with my YOUME Y368. It's started acting up, and I'm looking for a detailed service manual with boardviews and schematics to properly diagnose and repair it. I need to take precise voltage measurements around the board, so having the right documentation would be very helpful.

Thanks in advance for your help.

Selected Answer

I actually found that service manual on a tech Discord server a while back. A really helpful member there shared a direct link to their blog and I've saved it. I'm happy to pass it along here. Hopefully, these boardviews and schematics help you fix your phone, just like they got me through my repair. Looks like we have the same model.

@Erick

Absolute legend! That's exactly the info I was searching for. This is going to save me so much time probing in the dark. Seriously, thanks a ton for sharing the link!

Hi there,

I also have the YOUME Y368 and just downloaded the manual you shared. I'm pretty new to board-level phone repair, and this is a bit intimidating with all the tiny test points and the schematics. Could you point me in the right direction on how to start troubleshooting this ? Any advice on the first few things I should check would be a massive help.

Thanks so much for your time

General advices: start by checking the voltage at the battery connector on the board. With a known-good battery connected, you should see a steady voltage between 3.7V and 4.2V. After that, a great next step is to check the main power management IC (PMIC) for shorts. Using your multimeter in diode mode, check for shorts on the large input capacitors surrounding the PMIC.

Here are a few useful references for troubleshooting your device:
https://xdaforums.com/t/q-lock-pin-file-location.2801857/
Take a look at comment #1708
Also, this : https://www.ifixit.com/Answers/View/264191/Digitizer+still+not+working+on+5s.+Replaced+many+screens,+advice.
You can also check this video starting from minute 7:

The YOUME Y368 service manual and boardviews from the link above were exactly what I've been searching for. I couldn't find a complete, free copy anywhere else. Seriously, thank you for sharing this you're a lifesaver!

Hi everyone, I'm working on a YOUME Y368 with a no power issue and need some guidance with my measurements.
I'm detecting 3.3V on the VREG_MAIN line (pin 1 of the PMIC), which looks good, but I'm getting 0V on the VDD_CPU line (pin 8) where the schematics indicate I should see about 0.9V.
Since this is a core voltage for the application processor, could this missing rail be why the device shows no signs of life?
What's the best procedure to diagnose this further? Should I check for shorts on the CPU rail first, or look at the PMIC's enable signals?
I've already verified the main 3.3V and 1.8V power rails are present and stable.

My YOUME Y368 was working perfectly until yesterday when it suddenly went completely dead. Now it won't respond to the power button, doesn't vibrate, and shows no signs of life even when connected to a charger. I'm worried there might be a serious issue.

I have a decent multimeter, a basic soldering iron, and a healthy dose of patience. While I've successfully replaced iPhone batteries and charging ports, this will be my first attempt at actual diagnosis. The sheer density of BGA chips and microscopic components is honestly a bit overwhelming.

I'm particularly curious about the alcohol trick I've seen online where you apply isopropyl to the board and look for evaporation hotspots to locate shorts. Is this actually a reliable method for beginners, or are there better approaches I should try first with just a multimeter?

I learned this lesson the hard way last month with mine, it was declared "dead" by two different shops. The phone showed absolutely no signs of life - no charging indicator, no vibration, nothing. Before diving into complex board work, I decided to try one more basic test: wireless charging.

To my complete surprise, it actually heated up on the charging pad! This single discovery completely changed my diagnostic path. It turned out the issue wasn't with the main board or processor, but with the notoriously fragile USB-C port that had failed completely. A $15 replacement part and some careful soldering brought it back to life.

The moral? Always exhaust every external testing method before opening the device. Test wireless charging if available, try different charging methods, and don't assume the worst case scenario. Sometimes the most "dead" devices have the simplest solutions hiding in plain sight.

I suspect my issue might be related to that cheap, third-party fast charger I used at the airport last week... Now the device gets extremely hot during charging, the screen flickers at low brightness, and sometimes it randomly shuts down at 30% battery. Could this have damaged the power management IC or battery calibration?

If your YOUME Y368 starts acting up, random reboots, fast battery drain, or connectivity issues, there are several diagnostic steps you can take before assuming the worst:

• Check your charging habits: Using poor-quality chargers or wireless pads can gradually damage your battery and charging circuit, leading to unpredictable behavior.
• Inspect the physical components: A slightly damaged charging port, worn battery, or even accumulated pocket lint can cause issues that seem like major hardware failures.
• Monitor temperature patterns: If your phone gets unusually hot during specific tasks (like camera use or gaming), it could point to a failing component rather than a software issue.
• Use diagnostic tools wisely: Ampere for battery health, phone diagnostic codes (*#0*# on many models), and a thermal camera can reveal problems without opening the device.
• Know when to stop: If you see liquid damage indicators tripped or smell burnt electronics, it's time to consult a professional before causing irreversible damage.

Also visit this link it may help : https://xdaforums.com/t/which-fw-to-choose-2-2-or-2-2-2.1004130/

Here's what I discovered on forums and technical databases:

This guide will focus primarily on identifying and evaluating near-end echo, where the other person hears an echo of their own voice coming from your smartphone. If covering one speaker improves the bass response or makes it sound more "correct," it's a strong indicator of a polarity problem. "Burn-in fixer" apps for OLED are generally ineffective, as they cannot reverse physical degradation. Liquid Damage: Moisture can corrode the digitizer's circuitry, its flex cable, or the touch controller IC. Compromised Water and Dust Resistance: The most immediate consequence. Carefully inspect the area around the display connector and the backlight circuit components (driver IC, inductor, diode, capacitors). Carefully align the new display assembly and press it firmly into place. Carefully align and press the screen or back cover back into place, ensuring a snug fit. Finally, the relevant section of the motherboard itself, including the connector socket and the power/data lines leading to the camera interface, forms part of this intricate chain. Re-evaluate Custom ROMs: If a custom ROM is causing issues, try a different, more stable version, or revert to stock firmware. SIM/SD Card Tray: Ensure it opens and closes smoothly and aligns correctly. When this feature stops working, and you’ve ruled out a faulty charging pad or phone software, the culprit can often be a damaged wireless charging coil or, more specifically, its connector to the logic board. Cracked Solder Joints: Rings around component pins (especially on larger ICs or connectors) that indicate a break in the solder. Place one probe on the VBUS pin and the other on a known ground point (e.g., the metal casing of the USB port, a screw hole). If it’s a spring-loaded pin, ensure the spring is correctly seated and offers the right resistance. Before diving into troubleshooting, it's helpful to understand the main types of sensors: Overheating: Some hardware failures can cause the RF section to overheat. They are often found protecting USB ports against short circuits, as they offer a convenient self-resetting mechanism. Remove Old Flex Cable: If the LED is part of a larger front-facing sensor flex cable (e.g., housing the proximity sensor, ambient light sensor, or earpiece), and you've identified damage to that flex or suspect the LED on it is faulty: Trying this with just a jeweler's loupe or magnifying lamp is extremely difficult and prone to error. Location and Structure: Ideally, the repair shop should not be in an isolated area or one with easy street access that allows for quick smash-and-grab operations. Locate Battery Adhesive Tabs: iPhones typically use black adhesive pull tabs underneath the battery. If overheating persists after these steps, hardware inspection is warranted. Fine-Tip Soldering Iron: With adjustable temperature control and very fine tips (e.g., 0.1-0.3mm conical or chisel). This signal is routed from the phone's audio output (headphone jack) into an external audio interface. Caution: Restoring a damaged EFS backup can further complicate issues. Start by aligning one edge (often the top near the cameras or earpiece). A cheap battery might have inaccurate capacity, slow charging, or even swell dangerously. Use plastic pry tools and IPA (if needed) to carefully loosen and remove it. Inductor: A key component of the boost converter, storing energy magnetically and releasing it to step up the voltage.

@Shimaa, Not sure what you're trying to say but ok :)