[SOLVED] I'm looking for Sugar F7 LTE 64GB repair guide or schematics (free) - Phones & Tablets Forum

Hi,

I'm hoping you can help me out with my Sugar F7 LTE 64GB. 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.

@Eddie

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 Sugar F7 LTE 64GB 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/752323/CLP-510+Printer+%22Wasting+Data%22+and+no+printout
Take a look at comment #411
Also, this : https://xdaforums.com/t/a-question-about-g530fq.3330734/.
You can also check this video starting from minute 7:

The Sugar F7 LTE 64GB 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 Sugar F7 LTE 64GB 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 Sugar F7 LTE 64GB 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 Sugar F7 LTE 64GB 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/q-best-rom-for-battery-life.1466592/

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

Cracks often originate here due as these are points of stress concentration. To effectively analyze screen flickering, it's important to first categorize the symptoms. Factory Reset (Last Resort): If all else fails and you suspect a software issue, a factory reset (after backing up all data) can sometimes resolve deep-seated software conflicts. Cotton Swabs or Lint-Free Cloths: For drying and absorbing excess IPA. ESD Protection (Recommended): While Fairphones are generally robust, using an ESD wrist strap and mat is always good practice when handling internal electronics. Most inductors are non-polar, but confirming orientation is good practice. By diligently applying these multimeter techniques, you'll be able to identify a wide range of smartphone logic board issues, from simple broken fuses and open traces to complex short circuits and IC failures, making you a much more effective and confident repair technician.4. Component Failure: A faulty capacitor, inductor, or even a damaged flex cable (e.g., a shorted camera, display, or button flex) can create a short. If, after this comprehensive assessment, the issue is not resolved by replacing external accessories or cleaning the port, the problem likely lies within the phone's internal hardware. Plastic and metal spudgers: For prying open the device and disconnecting flex cables. This guide will focus primarily on troubleshooting the loudspeaker, as weak output from the earpiece is often a separate issue, though some diagnostic steps overlap. App Interference: If the color issue started after installing a new app, try uninstalling that app. Drops and Impacts: The force of a fall can easily deform the relatively soft aluminum or steel frames used in smartphones. When performing any internal repair or maintenance, always use appropriate tools and follow established procedures to avoid bending pins or damaging flex cables during reassembly. Form New Pad: Use a small amount of epoxy or UV-curable solder mask to create a new "pad" structure around the wire, then solder the wire to the component pin that was originally connected to this pad. Unlike traditional LCDs, OLED displays generate light for each pixel individually, resulting in vibrant colors, deep blacks, and excellent contrast. Part of the Back Cover/Glass: On some older or specific models, the antenna section might be a distinct plastic piece within the back cover itself, or sometimes even part of a plastic "window" on a glass back. Nearby Electronics: Keep the phone away from speakers, magnets (e.g., magnetic phone mounts, magnetic cases/folio covers), large metal objects, power lines, and other electronic devices during testing. Purpose: The single most crucial piece of personal ESD safety equipment. Lint-Free Cloths or Microfiber Towels: For wiping away softened residue. After cleaning, retest the microphone by making a call or recording a voice memo. For smartphone applications, always opt for a high-quality, non-electrically conductive thermal paste with good thermal conductivity. You'll need to carefully remove old adhesive and apply new, proper adhesive for a secure reassembly and to restore any water resistance. Antivirus/Firewall: Temporarily disable your antivirus or firewall to see if it's blocking the USB connection (remember to re-enable it afterward). Delicate Components: Handle coaxial cables and their connectors with extreme care. Replacement: If a coil is found to be damaged (open circuit, physically cracked, burnt), the only reliable repair is replacement. Adaptive Brightness/True Tone: Features like Apple's True Tone or Android's Adaptive Brightness (or similar ambient display settings) can adjust screen color temperature based on ambient light. Component Sourcing: Finding the exact replacement IC can be difficult; donor boards are often the best source. Disconnect Relevant Flex Cables: Identify and carefully disconnect any flex cables that cross over or connect to the charging port module. All these tapes work by creating a conductive barrier that either reflects or absorbs electromagnetic waves, directing them to ground and preventing them from affecting sensitive circuits.

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