[SOLVED] I'm looking for Xiaomi Redmi 2 repair guide or schematics (free) - Phones & Tablets Forum

Hi,

I'm hoping you can help me out with my Xiaomi Redmi 2. 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.

@Daniela

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 Xiaomi Redmi 2 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://www.ifixit.com/Answers/View/6807/Formac+Studio+FS10+Video+Converter+will+not+convert+Wii+signal
Take a look at comment #33
Also, this : https://xdaforums.com/t/question-backup-and-restore.3515543/.
You can also check this video starting from minute 10:

The Xiaomi Redmi 2 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 Xiaomi Redmi 2 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 Xiaomi Redmi 2 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 Xiaomi Redmi 2 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/Guide/Power+Mac+G4+Quicksilver+Video+Adapter+Replacement/2126

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

Fortunately, most update failures can be resolved through a series of troubleshooting steps, from basic checks to advanced firmware flashing. iOS: Go to Settings > General > Transfer or Reset iPhone > Reset > Reset Network Settings. These chips are usually smaller and have fewer pins, making them slightly less complex than the main baseband CPU. The jig ensures even distribution of force, minimizing localized stress points. You might need to add a tiny bit of fresh, standard lead-free solder to the wick or iron to help "wash" away the bismuth alloy. They allow technicians to perform tasks more quickly, accurately, and with less effort. "No Service" or "Searching" Constantly: Even in areas with strong cellular coverage. While a simple dead battery or screen might be the culprit, a persistent no-power issue often points to deeper problems within the logic board's power delivery system or critical ICs. Reheat as Needed: Continuously reheat sections as you work your way around the perimeter. Before fully closing the device, perform a final visual check to ensure all cables are correctly seated, free of obstruction, and clear of any screw posts or mating surfaces. A fiberglass pen or a very sharp, light touch with an X-Acto knife is suitable. ESD-Safe Mat and Wrist Strap: To prevent electrostatic discharge damage. iPhone 6s/7/8/SE 2nd Gen: The display opens like a book from the right side. Improper Connection: Connecting the battery slightly off-center can cause arcing and damage. Look for any apps exhibiting unusually high usage, especially those you haven't actively used. Inefficient software/firmware: Poorly optimized OS or app software might not manage resources effectively, leading to premature heat buildup. Understanding the different types of UV glues and their proper application is vital for any modern smartphone repair technician. Cooling: Immediately move both separated board halves away from the heat source and allow them to cool naturally on a heat-resistant surface. If the issue seems to be isolated to your smartphone, focus on its internal settings and software: Missing Components: Severe corrosion can completely destroy solder joints, causing small surface-mount components (resistors, capacitors, tiny ICs) to detach from the board. An oscilloscope would display the waveforms, clearly showing if one speaker's waveform is inverted relative to the other's. Diagnose Power Issues: Trace power rails, identify missing voltages, and locate short circuits to ground. Be extremely cautious of delicate ribbon cables connecting the display. The principle behind glass polishing is simple: use an abrasive compound to gradually remove microscopic layers of glass until the bottom of the scratch is reached and the surface is uniform. Connect Flexes: Reconnect all flex cables to the logic board or other components, ensuring they are seated correctly and click/latch into place. If the old pad crumbles or is very sticky, you might need to carefully scrape off larger pieces, then use a lint-free wipe dampened with IPA to clean any residue from both the component surface and the mating heatsink/frame surface. Loudspeaker (Bottom Speaker/Multimedia Speaker): This is the larger speaker, usually located at the bottom of your phone. Troubleshooting: Compare the observed current signature to known good ones. It demystifies the technology we rely on daily, offering a glimpse into its intricate internal workings. Common issues include distorted sound, no sound at all, low volume, or crackling noises.

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