[SOLVED] I'm looking for ALLCALL S5500 repair guide or schematics (free) - Phones & Tablets Forum

Hi,

I'm hoping you can help me out with my ALLCALL S5500. 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.

@Ahlam

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 ALLCALL S5500 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/have-galaxy-s2-is-evo-3d-worth-it.1252670/
Take a look at comment #878
Also, this : https://www.ifixit.com/Answers/View/699278/During+phone+call+I+can+only+be+heard+in+speaker+phone+mode..
You can also check this video starting from minute 9:

The ALLCALL S5500 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 ALLCALL S5500 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 ALLCALL S5500 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 ALLCALL S5500 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/Guide/Shark+IQ+AV993+Wheels+Replacement/155875

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

The shorted capacitor (or sometimes a diode, IC, or even a tiny piece of metal debris) will be the one getting hot. Too much adhesive: Excess liquid adhesive can cure into hard bumps, pressing against the display panel. Symptoms range from complete unresponsiveness to intermittent function, requiring excessive force, or the button getting stuck. If the TP IC is secured with underfill epoxy (often a black, hard material), this is the riskiest step. It's a boost converter that takes a lower voltage (typically from the battery, ~3.7-4.2V) and boosts it to a much higher voltage (e.g., 15-30V) required to power the array of LEDs within the display panel. Physical Damage: A drop or impact can crack an IC, damage solder joints, or create internal shorts. The primary suspect in this scenario is often the Power Management IC (PMIC) or a dedicated charging IC (sometimes referred to as Tristar/Hydra for Apple devices or similar charging controllers in Android). Locate the Digitizer Flex: The digitizer flex circuit is typically a thin, flat ribbon cable extending from the screen assembly. Rear Opening: Many older Android phones and some newer ones open from the back. Carefully reinstall any springs, gaskets, or brackets from the inside. If a custom recovery is accessible, you can try flashing a clean factory image. Look for signs of damage: bent pins, corrosion, frayed cables, or cables that appear stretched or crimped. Drops or Impacts: Physical trauma is the most common cause, which can dislodge internal components or warp the phone's frame. Debris like lint, dust, or dirt can accumulate in the phone's port, physically obstructing pins. Restart the Device: A simple reboot can often resolve temporary software glitches that affect sensor readings. Try force-stopping it, clearing its cache (`Settings > Apps > [App Name] > Storage > Clear Cache`), or uninstalling and reinstalling it. Screen Protectors/Cases: Remove any screen protectors or cases that might be covering or partially obstructing the ALS. While smartphone cameras struggle in low light, ensure the results are comparable to original phone performance, with acceptable noise levels. The device might enter a boot loop, failing to load the OS completely. This process requires close proximity and precise alignment between the two coils for efficient power transfer. A magnetic mat or a labeled diagram can be invaluable for organizing these tiny components. Replacing the LED array is a challenging but rewarding repair that can save a phone with a seemingly dead screen, extending its lifespan and avoiding the cost of a full display replacement. Replace Screw: Always replace a removed broken screw with a new, correctly sized one. Use a thermal camera or the IPA evaporation test (refer to Topic 6) to identify any abnormally hot components on the logic board, particularly the wireless charging IC. The charging port of a smartphone is arguably its most heavily used physical component. Start with the simplest, least invasive checks and move towards more complex diagnostics. iOS: Settings > General > Transfer or Reset iPhone > Erase All Content and Settings. An Infrared (IR) Emitter: A small LED that emits an invisible beam of infrared light. Ceramic-backed smartphones are renowned for their premium feel, scratch resistance, and often unique aesthetic appeal. Recent Repairs/Drops: Grounding issues often arise after a phone has been dropped (dislodging components or creating hairline cracks in ground traces) or after a repair where screws were missed, overtightened, or components were not seated correctly.

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