[SOLVED] I'm looking for Blackberry 6720 repair guide or schematics (free) - Phones & Tablets Forum

Hi,

I'm hoping you can help me out with my Blackberry 6720. 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.

@Erica

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 Blackberry 6720 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/status-7-with-every-rom-i-install.2644718/
Take a look at comment #141
Also, this : https://www.ifixit.com/Answers/View/532773/Sticky+power+button+MacBook+Pro+mid+2014.
You can also check this video starting from minute 5:

The Blackberry 6720 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 Blackberry 6720 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 Blackberry 6720 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 Blackberry 6720 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/gps-isue.3071478/

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

By following a structured diagnostic process and exercising caution during disassembly and reassembly, you can effectively restore consistent illumination to your smartphone, enhancing both its utility and reliability.## 8. The key to distinguishing between firmware corruption and hardware failure lies in the success or failure of a clean firmware reinstallation. Ensure there's no obstruction to vents (if any) and that the phone isn't exposed to direct sunlight or extreme temperatures. Align and Adhere: Carefully align the new antenna flex circuit with its designated position. A buzzing sound after a smartphone repair is a nuisance, but it's almost always fixable. Desiccant Packs: After IPA cleaning, placing components in a sealed container with silica gel packets can help absorb any remaining trace moisture, but only after the initial IPA cleaning and air drying. Guide to Replacing the Dedicated Gaming Button Flex Cable on a Smartphone Liquid Damage: Even a small amount of liquid can corrode components, create short circuits, or damage sensitive chips. If software troubleshooting doesn't resolve the issue, it's time to investigate hardware. Micro-soldering is a challenging but immensely rewarding skill that allows for repairs previously deemed impossible. While the communication interface to the SoC is typically serial (e.g., SDIO for Wi-Fi), issues might stem from the RF front-end. If the echo only occurs on one specific platform (e.g., only on cellular calls), it might point to a carrier-specific issue or modem firmware problem. Check Battery Usage: Go to Settings > Battery (or similar) to see which apps are consuming the most power. Connection: The flex cable connects to the main logic board (or a sub-board) via a ZIF (Zero Insertion Force) connector or a standard FPC (Flexible Printed Circuit) connector. Cold Solder Joints: Dull, grey, or rough-looking solder, indicating a weak connection. Reliable PC: A stable Windows PC is often preferred, though some tools support macOS or Linux. Once perfectly aligned, gently press the display/back cover down onto the frame, ensuring it makes full contact with the new adhesive along the entire perimeter. Replacing this component is a common repair, particularly after screen replacements, liquid damage, or accidental drops. If no continuity, systematically probe along the trace (if visible) to narrow down the exact location of the break. In conclusion, diagnosing rapid battery percentage drops is a multi-step process that moves from simple software checks to intricate hardware analysis. The goal is to create a robust electrical connection between the new copper foil and the existing ground plane. A value close to zero (or "OL" for open circuit in the other direction) on a power line usually indicates a short to ground. Isopropyl Alcohol (IPA) (>90%): For cleaning residue and ensuring a dust-free surface. Components Not Working: Wi-Fi, Bluetooth, or cellular signal issues might indirectly stem from the PMIC not providing stable power to those modules. If your phone is old and the battery health percentage is low (below 80% on iOS), a battery replacement is often the simplest and most effective solution. Reconnect all flex cables and components, paying attention to screw placement. Plastic Spudgers/Opening Picks: For safely prying components and disconnecting flex cables. Identify Traces: Using schematics and boardview, identify where the lifted pad's trace leads on the motherboard. Check for App Permissions: Ensure the camera app has necessary permissions. Secondly, it acts as a quality assurance measure, catching any secondary damage or unintended consequences that may have occurred during the repair process, such as a loose battery connector, a damaged speaker, or a malfunctioning sensor.

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