[SOLVED] I'm looking for Lenovo A805e repair guide or schematics (free) - Phones & Tablets Forum

Hi,

I'm hoping you can help me out with my Lenovo A805e. 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.

@Pauline

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 Lenovo A805e 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/lg-g-watch-giveaway.2840306/
Take a look at comment #1072
Also, this : https://xdaforums.com/t/does-rom-effect-on-gpu-or-cpy.2197757/.
You can also check this video starting from minute 9:

The Lenovo A805e 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 Lenovo A805e 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 Lenovo A805e 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 Lenovo A805e 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/google-books-no-basket-cart-so-cant-buy-books.3443950/

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

Logic Board Repair: Replacing power management ICs or other damaged components. Locate the Storage Chip: Using schematics and boardview software, identify the eMMC/UFS chip on the logic board. Any breaks in the line or unresponsive areas pinpoint specific digitizer failures. Negative Temperature Coefficient (NTC) thermistors are commonly used, meaning their resistance decreases as temperature increases. Reinstalling iOS software is a powerful troubleshooting method for iPhones and iPads that are experiencing persistent software issues, boot loops, performance problems, or preparing a device for a new owner. Smartphone Itself: Built-in battery usage statistics, notification logs, developer options. Corrosion/Liquid Damage: Green or white residue on contacts or antenna elements indicates liquid damage, which can disrupt continuity. Before fully reassembling the phone, it’s prudent to perform a preliminary test. For smartphone applications, always opt for a high-quality, non-electrically conductive thermal paste with good thermal conductivity. Liquid damage/corrosion: White/green residue around the IC or its pins. This repair is generally straightforward for most models, requiring careful disassembly and component replacement rather than intricate soldering. Use a thermal camera to identify any rapidly heating components in the baseband area. If overheating persists after these steps, hardware inspection is warranted. It's not a casual undertaking and requires a significant degree of technical understanding, patience, and careful adherence to instructions. Hardware Limitations: The phone's 5G modem and antenna design play a significant role. Boot into Safe Mode: If the issue persists, boot your phone into safe mode (check your phone's model for specific instructions). Restart Phone: A simple reboot often clears temporary software glitches. If these lines are partially damaged or shorted, the phone might only revert to a basic, slow "dumb" charging mode. Method: Plug the phone into a known-good charger and wall outlet, letting it charge for at least 30 minutes, or until the charging indicator appears stable. Factory Reset: As a last resort for persistent software-related stuttering, a factory reset can often resolve deep-seated software issues by returning the phone to its "out-of-the-box" state. The charging indicator might not appear at all, or it might just briefly flash. Display Removal (Less Common, but applicable to some models): Some phones open from the front. Therefore, a comprehensive backup of your device's data is not just recommended, but absolutely essential. However, this is extremely complex, requires specialized tools (hot air station, microscope, chip programmer), and often involves overcoming software limitations (e.g., security pairing between the chip and CPU). Expose enough bare copper trace to solder to (typically 0.5mm to 1mm). Ensure the BGA adapter is clean and the chip is seated correctly (for direct method). In conclusion, replacing the main SoC on a smartphone logic board is a testament to the extremes of micro-soldering. Using your hot air station (or fine-tipped soldering iron), gently heat the component and its pads. Consistency: Use the same testing conditions (dark room, max brightness, pure black image) for accurate and repeatable results. Drag Soldering ICs: The flat edge allows for efficient drag soldering of integrated circuits (ICs) with fine-pitch pins (e.g., smaller BGA/LGA components, charging ICs).

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