[SOLVED] I'm looking for Xiaomi Redmi 1S repair guide or schematics (free) - Phones & Tablets Forum

Hi,

I'm hoping you can help me out with my Xiaomi Redmi 1S. 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.

@Bobby

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 1S 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/bootloader-v4-23-android-4-3-jwr66v-n7-wi-fi-grouper.2379970/
Take a look at comment #340
Also, this : https://xdaforums.com/t/build-prop-reverting-to-original-after-reboot.3752262/.
You can also check this video starting from minute 8:

The Xiaomi Redmi 1S 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 1S 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 1S 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 1S 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/838642/My+Triggers+are+stuck+at+%100

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

Clean Thoroughly: After polishing, meticulously clean the lens and surrounding area to remove all abrasive residue. For larger cracks or small missing pieces: Use a plastic-specific filler or a small amount of clear epoxy. Unscrew the bracket, then use a plastic spudger to gently pry up and disconnect the battery flex cable. Often, the cost of a new motherboard plus labor approaches or exceeds the cost of a new budget or mid-range smartphone. The goal here is to blend the low-temp solder with the original, higher-melting-point solder. To ensure optimal adhesion and a strong, consistent seal, it is highly recommended to apply sustained pressure to the phone after reassembly. Carefully route the jumper wire along the path of the original trace, avoiding any other components or potential short circuits. Data Recovery: If the phone is dead but critical data is needed, specialized services can sometimes extract data from severely damaged motherboards. If a part doesn't move easily, re-evaluate if there are hidden screws, clips, or adhesive. Slowly and gently work your way around the entire edge of the display, carefully slicing through the adhesive. Try drawing lines with varying degrees of pressure to see if the line thickness changes accordingly. A broken proximity sensor can severely degrade the calling experience and, in some cases, affect other apps that rely on proximity detection. Gather necessary tools: specific screwdrivers (pentalobe, Phillips, tri-wing), spudgers, suction cup, opening picks, heating pad/heat gun (for models with adhesive-backed displays/backs). Data Loss During Transfers: Files transferred to or from the device may be corrupted or lost during the process. If visual inspection doesn't reveal an obvious fault, or if the issue is intermittent, electrical testing is necessary. Record Your Voice: Use your phone's built-in voice recorder app (or a third-party alternative). Grounding: Proper grounding paths throughout the device are crucial to dissipate unwanted electrical noise. A full firmware reflash (e.g., via Odin or Fastboot) also overwrites system and data partitions, effectively erasing everything. Common causes of failure include physical impact (drops), liquid damage, or rarely, a manufacturing defect or general wear and tear. This typically involves disassembling the phone, locating the affected speaker(s), and physically reversing the connections. Remove Old Module: Once disconnected and unsecured, carefully lift the old flex cable containing the secondary microphone out of the phone. As the solder balls/pads melt, the IC will self-center and "snap" into place due to surface tension. ESD-Safe Mat and Wrist Strap: To prevent electrostatic discharge, which can damage sensitive electronic components. Intermittent Power Issues: Phone randomly shuts off, restarts, or fails to power on consistently. Debris can trap moisture and accelerate the oxidation process, and itself can cause connectivity issues. The primary storage chip, whether it's an eMMC (embedded MultiMediaCard) or the newer, faster UFS (Universal Flash Storage), is the digital brain of a smartphone. By following these steps, you can restore your smartphone's visual appeal and ensure its vital communication channels remain unimpeded, giving your device a renewed lease on life. Carefully examine the motherboard and internal components for signs of liquid residue, corrosion, or physical damage (dents, cracks). Logic Board Damage: If the touch controller IC (Integrated Circuit) on the logic board is damaged (e.g., from severe drops or water damage), even a new screen won't fix it. Limited Shadow Curing: Areas not exposed to UV light may not cure properly.

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