[SOLVED] I'm looking for Oppo A77 V1 128GB repair guide or schematics (free) - Phones & Tablets Forum

Hi,

I'm hoping you can help me out with my Oppo A77 V1 128GB. 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.

@Vishal

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 Oppo A77 V1 128GB 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/unable-to-find-satellites-or-lock-on-with-v980-with-custom-rom.2802503/
Take a look at comment #1127
Also, this : https://xdaforums.com/t/andrid-nougat-7-0-for-s5-sm-g900f.3447886/.
You can also check this video starting from minute 10:

The Oppo A77 V1 128GB 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 Oppo A77 V1 128GB 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 Oppo A77 V1 128GB 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 Oppo A77 V1 128GB 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/Teardown/Punkt+MP02+Teardown/164257

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

Follow recommended temperature profiles for lead-free solder (typically around 350-380°C with moderate airflow). Given its delicate nature and the high number of tiny pins it contains, this connector is highly susceptible to damage from drops, liquid exposure, or improper handling during repairs. Replacing a smartphone fingerprint sensor is a common repair, though its complexity varies significantly depending on the device's design and the sensor's integration. Connector Stuck: If the connector isn't coming off easily, it means the solder isn't fully molten on all points. The primary goal is always to gain access to the internal components without causing further damage, which often means carefully navigating adhesive seals, tiny clips, and fragile flex cables. Solder Joint Integrity: For phones that have been dropped, microscopic inspection of the solder joints under RF ICs and their surrounding components can reveal micro-cracks. You'll need a Windows PC, correct USB drivers for your phone (ADB and Fastboot drivers are a good starting point), and the appropriate flashing tools. This creates miniature electrochemical cells that rapidly corrode the metal, forming non-conductive oxides or even shorting pathways. This is often a relatively straightforward swap once the phone is open. Does it return to the home screen? Does it trigger multitasking or voice assistant as expected? Precision and Heat Management: Desoldering and resoldering BGA components requires a specialized BGA rework station, which precisely controls heat profiles to melt all solder balls simultaneously without overheating or damaging the chip or surrounding components. Detecting moisture exposure can sometimes be straightforward, but often requires a keen eye for subtle clues, both external and internal, as well as an understanding of the device's behavior. If using a heat gun, apply very low heat (e.g., 60°C / 140°F) in short bursts while under pressure, moving constantly. Excessive Heat: The phone (specifically the area around the PMIC) gets unusually hot, even without heavy usage, suggesting a component drawing too much current or a short. Pins: Check the pins within the connector on the logic board for any bends, breaks, or corrosion. Force Restart: If the screen is too unresponsive to power off normally, perform a force restart. Final Inspection: Perform a final visual inspection under the microscope. Ensure any alignment pins or brackets seat correctly and the speaker grille aligns with the opening in the frame. Antenna System: Damaged coaxial cables, antenna flexes, or antenna connectors are common and simpler causes of "no service." This flexibility is crucial as it allows the entire assembly to be bent and folded into tight spaces within the smartphone chassis. If software and network-side troubleshooting don't resolve the issue, the problem likely lies with the smartphone's Wi-Fi hardware. The device's screen will remain completely black, but iTunes/Finder will still detect it in "Recovery Mode." However, internally, DFU mode bypasses the operating system and bootloader entirely, communicating directly with the device's hardware. If the microphone clarity issue persists after a factory reset (after backing up all important data), it strongly suggests a hardware problem. Thermal Paste/Pads (Optional): Some cooling systems are integrated with heat sinks that require fresh thermal paste or pads if disturbed. Android: Go to `Settings > Accessibility > Color and motion` (or `Visibility enhancements`). If you suspect excessive thermal throttling beyond what's considered normal for your device, especially after eliminating environmental and software factors, it's advisable to consult with the manufacturer's support or a professional repair service. Resetting network settings does not erase data but resets Wi-Fi, cellular, and VPN settings. Hardware Check: If software solutions fail, inspect the battery for physical signs of degradation or swelling. When the power button is pressed (simulating closure, you can use tweezers to short the appropriate pins if the flex is off), this voltage should drop to near 0V. 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.

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