[SOLVED] I'm looking for CITYCALL E808 repair guide or schematics (free) - Phones & Tablets Forum

Hi,

I'm hoping you can help me out with my CITYCALL E808. 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.

@Kristine

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 CITYCALL E808 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/q-cyanogen-mode-9-for-xperia-mini-mini-pro-active-lww.1710563/
Take a look at comment #1260
Also, this : https://xdaforums.com/t/q-how-to-submit-an-idea-for-android-accessories.3079045/.
You can also check this video starting from minute 8:

The CITYCALL E808 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 CITYCALL E808 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 CITYCALL E808 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 CITYCALL E808 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/closed-share-aurorastore.4621715/

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

When a speaker is replaced, or when the phone is disassembled for other repairs (like screen or battery replacement), if the speaker is reconnected incorrectly, meaning the positive and negative terminals are reversed, it will result in a polarity issue. Apply a tiny amount of precision adhesive (e.g., B7000) to secure the flex cable in place. Thoroughly test the new display: ensure no lines, check for dead pixels, test touch functionality across the entire screen, and verify all transferred components (cameras, sensors, home button) are working correctly. Carefully adhere the wireless charging coil and NFC antenna in their correct positions. If speakerphone/headphones also have issues: The problem might be with the audio codec IC on the motherboard, the microphone, or general software/network issues, not just the earpiece. The flex cable transmits the electrical signal to the system when the switch is pressed. This connection is vital for electromagnetic interference (EMI) shielding, preventing external noise from affecting internal components and containing internal noise from radiating outwards. Disassembly: Following a specific repair guide for your phone, carefully open the device to gain access to the charging port assembly. While display replacement fixes most touchscreen issues, sometimes the problem lies deeper: Research Your Specific Model: Search for a detailed teardown guide or video for your exact phone model (e.g., "iFixit iPhone 11 Power Button Replacement" or "Samsung Galaxy S20 Power Flex Replacement YouTube"). It could mean the screw is not fully tightened, is the wrong size, or the internal component it's meant to secure is not properly seated. This detailed evaluation sets the stage for potential component replacement or professional micro-soldering intervention.## 10. By following these comprehensive backup steps, you can confidently hand over your smartphone for repair, knowing that your valuable data is safe and secure, ready to be restored to your device once it's returned to you or transferred to a new replacement phone. Oxidization, often appearing as green, blue, or white crystalline deposits, immediately attacks solder joints, traces, and component pins, disrupting electrical pathways. This means the phone's internal system is running, but the display isn't. Separate the back cover: Once you have a small opening, slide the opening pick or plastic spudger around the perimeter of the phone, slowly cutting through the adhesive. Proper recycling allows for the recovery of these finite resources, reducing the need for new mining and its associated environmental impact. Top and Bottom Layers: These are the outer layers, where most of the surface-mounted components (ICs, resistors, capacitors, connectors) are placed and directly soldered. Capacity: If your iOS device reports maximum capacity below 80%, or if third-party apps on Android consistently show significantly reduced estimated capacity, it's a good time to consider replacement. Low Volume: Even at maximum volume, the caller's voice is too quiet to hear clearly. They usually have tiny, snap-on connectors on each end, often referred to as U.FL or IPEX connectors, though some devices might use slightly different proprietary designs. Use a multimeter in continuity mode to check the integrity of the flex cables. Once a hot spot is identified, use your microscope to examine the area closely. Its ability to accurately detect and interpret multiple simultaneous touch inputs, known as multi-touch, is crucial for gestures like pinch-to-zoom, two-finger scrolling, and multi-finger gaming controls. Allow Device to Cool: If the phone has been in active use, let it cool down for a few minutes before opening. VoLTE/Wi-Fi Calling: These features can sometimes interfere with band switching if not properly implemented or supported. A thermal camera can quickly identify hot spots on the logic board, indicating the location of the short. Carefully examine your screen for any visible cracks, pressure points, or signs of impact damage. Erratic or Inaccurate Touch: Touches are registered in the wrong location, or gestures are misinterpreted. Excessive Cold: If the phone is very cold, warm it up gradually to room temperature.

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