[SOLVED] I'm looking for Micromax Yu Yureka S repair guide or schematics (free) - Phones & Tablets Forum

Hi,

I'm hoping you can help me out with my Micromax Yu Yureka S. 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.

@Holly

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 Micromax Yu Yureka S 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/399727/Is+my+espresso+maker+dead+or+can+I+repair+it
Take a look at comment #845
Also, this : https://www.ifixit.com/Answers/View/306656/Bootloop+++no+pc+connection+usb.
You can also check this video starting from minute 6:

The Micromax Yu Yureka S 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 Micromax Yu Yureka S 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 Micromax Yu Yureka S 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 Micromax Yu Yureka S 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/746516/My+M30+Wi-Fi+is+not+working+properly

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

While drastic, it completely rules out any software-related corruption or deep-seated configuration issues that might be preventing proper Wi-Fi operation. Use the multimeter to perform a continuity check from the charging port pin (now connected via the jumper) to the original destination component. Component Shields: Remove any EMI shields covering the components on the outer surfaces of the boards that are easily accessible. Logic Board & Components: Look for visible water droplets, dried residue, discoloration, or corrosion on the Printed Circuit Board (PCB) and its components. This cuts off power to the logic board, preventing accidental short circuits and protecting both you and the device during the repair process. Finger Test (Caution!): With a very low voltage and current, you might be able to very carefully and briefly touch components with your finger to feel for heat. Appearance: Small, often gold-plated pads or vias (through-holes) on the PCB. Cellular: Insert a SIM card and test network registration, calls, data, and SMS. Ensure the conductive side of the tape makes firm contact with a ground point on the logic board or the metal frame of the phone. If you have a backup of the EFS partition (taken before the issue occurred, often using custom recovery like TWRP or specialized tools), you can try restoring it. These sensors are often integrated into the power button, providing a convenient and intuitive placement. Debris: Check for lint, dust, pocket fluff, crumbs, or any foreign objects obstructing the port. Diagnosing Intermittent Issues: Some problems manifest only during active use or under specific OS conditions. Inspect Connector: Under the microscope, meticulously examine the damaged U.FL/IPEX connector(s). Once in recovery, you'll see either a stock recovery menu or a custom recovery like TWRP. Test with Multiple Chargers: Try several known-good wireless charging pads. BGA Package: Most PMICs are Ball Grid Array (BGA) components, meaning their solder connections are tiny balls located entirely underneath the chip. Detecting Open Circuits: A reading of `OL` (Over Limit) or infinity where there should be continuity (e.g., a fuse) indicates an open circuit. Flux (for soldered ports): No-clean liquid or paste flux to aid solder flow. Interrupted Firmware Flashing: If an update or custom ROM flash is interrupted or goes wrong, it can lead to a soft brick, often resulting in a Recovery Mode loop. In conclusion, proper smartphone frame preparation before re-assembly is not merely a suggestion; it is a fundamental requirement for a high-quality, durable, and aesthetically pleasing repair. Focus Areas: Pay particular attention to areas known to generate heat or where power-intensive components are located. Regular Backups: Back up your data regularly to cloud services or your PC. By systematically working through software and hardware troubleshooting steps, you can usually identify and resolve the problem, restoring full USB functionality to your smartphone. Sometimes, a slightly larger Phillips bit might grip a slightly stripped Phillips screw better if the outer edges are still intact. IC Removal (e.g., PMICs, Wi-Fi ICs, USB Charging ICs, CPU Shields): These components are frequently ball grid array (BGA) packages, meaning their connections are underneath the chip. The data extracted is raw and unencrypted, making it useless if the device's encryption is active. Issues: Prone to dents, deep scratches, scuffs, and wear of anodized or painted finishes. Update OS/Firmware: Ensure the latest operating system and any modem firmware updates are installed. Use a Known White/Gray Reference: Take photos of a plain white sheet of paper or a professional gray card under various lighting.

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