[SOLVED] I'm looking for Samsung SM-A235M Galaxy A23 repair guide or schematics (free) - Phones & Tablets Forum

Hi,

I'm hoping you can help me out with my Samsung SM-A235M Galaxy A23. 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.

@Catalina

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 Samsung SM-A235M Galaxy A23 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/kernel-discontinued-fustercluck-kernel-39a-cm-aosp-stock.3085676/
Take a look at comment #1484
Also, this : https://xdaforums.com/t/cant-flash-back-to-stock.2268854/.
You can also check this video starting from minute 6:

The Samsung SM-A235M Galaxy A23 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 Samsung SM-A235M Galaxy A23 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 Samsung SM-A235M Galaxy A23 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 Samsung SM-A235M Galaxy A23 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://www.ifixit.com/Answers/View/814452/The+screen+is+dead+but+I+hear+atuff

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

Clean the Area: With the old sensor removed, thoroughly clean the area beneath it. If this is the cause, the dust specks are usually visible from the very first use of the phone. Clean Pads: Clean the pads with desoldering braid and isopropyl alcohol. Apply a small but adequate amount of flux to the area you intend to solder before applying heat or solder. The primary method for fixing a smartphone stuck in EDL mode involves using specific Qualcomm flashing tools to re-flash the correct stock firmware onto the device. Open a command prompt/terminal where your ADB/Fastboot tools are located. Mid-frames can be made of various materials, including aluminum alloys, stainless steel, or various plastics. Remove Battery (if easily removable): For older phones with user-removable batteries, this is the first hardware step. Purpose: Ensure the electrical pathways on the flex cable are intact from the switch to its connector pins. This guide provides a comprehensive framework for carefully preparing, categorizing, packaging, and storing disassembled smartphone components, ensuring their longevity and readiness for when they might be needed again. Fuses are commonly found in power delivery paths, such as the main battery input, charging circuits, backlight circuits, and sometimes specific peripheral power lines. Disable/Enable Haptic Feedback: Toggle the haptic feedback setting off and then back on. You might find usage statistics, estimated remaining life, and sometimes temperature, but usually not a direct health percentage. A faulty BMS might incorrectly report battery status, leading the phone to refuse charging or to charge erratically. Apply heat evenly and gently, avoiding prolonged heating of any single spot. Diagnosing a smartphone that refuses to power on, often referred to as a "dead phone," can be one of the most challenging yet rewarding aspects of board-level repair. Extreme cold can also temporarily affect battery performance and screen responsiveness. Frequent App Crashes: Apps suddenly close without warning, especially resource-intensive ones (games, video editors, browsers with many tabs). Smartphone motherboards are incredibly complex and densely packed with miniature components, solder joints, and multi-layered circuit traces. Use a suction cup and thin prying tools to carefully separate the screen from the frame. Insert SIM Card: Insert a known good SIM card into the newly installed reader. Reset Network Settings: This action resets Wi-Fi, mobile data, and Bluetooth settings, but crucially, it can also affect location-related services and their configurations. Align it perfectly, ensuring the cutouts (for camera, speaker, sensors) match up with your phone's features and the edges are symmetrical. The best strategy is always prevention: perform regular backups to avoid the stress and potential loss of irreplaceable memories.8. Next, try to boot the device into Safe Mode (for Android) or a similar diagnostic state. Manufacturer-Specific Tools: Sometimes, official or semi-official service tools used by repair centers can bypass FRP. Updates often include critical bug fixes, improved driver support, and enhanced compatibility for external peripherals. Even normal wear and tear, especially if the phone is frequently opened for repairs or battery replacements, can contribute to the degradation of the delicate contacts. Connect Internal Components: Before sealing, ensure all internal components are properly connected (cameras, sensors, buttons, charging port, etc.). A very low resistance (near 0 ohms) indicates a short, which would trigger OCP.

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