[SOLVED] I'm looking for LOGICOM L-ite 504 HD repair guide or schematics (free) - Phones & Tablets Forum

Hi,

I'm hoping you can help me out with my LOGICOM L-ite 504 HD. 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.

@Maha

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 LOGICOM L-ite 504 HD 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/511549/Dryer+will+not+turn+back+on+after+load+was+done
Take a look at comment #157
Also, this : https://xdaforums.com/t/q-moto-g-2nd-gen-stuck-on-reboot.3114585/.
You can also check this video starting from minute 4:

The LOGICOM L-ite 504 HD 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 LOGICOM L-ite 504 HD 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 LOGICOM L-ite 504 HD 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 LOGICOM L-ite 504 HD 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/Answers/View/433605/camera+suddenly+not+working

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

Whether you're trying to navigate an unfamiliar city, stream your favorite music, or simply load a webpage, sluggish data can bring your digital life to a grinding halt. Their use highlights the sophisticated evolution of smartphone repair, demanding specialized tools and an even higher level of technical expertise.How to Fix a Vibrating/Buzzing Sound in a Smartphone After Repair This typically requires professional diagnosis and often a motherboard replacement or re-balling of the chip, which is an advanced and expensive repair. Thermal Paste/Pads: These are applied directly between the heat-generating component (e.g., SoC) and a heat spreader. Microscope Inspection: Examine the PMIC and surrounding components for any signs of physical damage, overheating (discoloration), or compromised solder joints (e.g., due to physical impact or thermal stress). If the new camera works: The original camera module (which includes its flex cable) was faulty. Factory Reset (Last Software Resort): As a last resort for software issues, a factory reset can rule out deep-seated software corruption. Digital Microscope/Jeweler's Loupe: For inspecting tiny components, solder joints, or corrosion in extreme detail. Identify the Damaged Clip: Carefully inspect all flex cable connections on the logic board, battery, and other modules for missing or broken plastic clips. Advanced Polishing for Glass Lenses (High Risk, Professional Skill Recommended) These antennas connect to the main logic board via a small coaxial cable (U.FL/IPEX connector) or spring contacts. Mobile Device Management (MDM) locks are enterprise-level security measures for devices owned by companies or educational institutions. Diagnosing a smartphone with no display output requires patience and a methodical approach. A short or excessive draw on these rails points to the FEM or its surrounding components. Liquid Ingress: Moisture can corrode the delicate electronics within the camera module or its flex cable, leading to intermittent or complete failure. Place the suspect part side-by-side with a genuine one and meticulously compare all aspects: markings, materials, colors, textures, and even weight. The internal landscape of a smartphone is a miniature metropolis of intricately placed components, each secured by a multitude of incredibly tiny screws. The phone shows the Android boot animation for a few seconds/minutes and then restarts. Component Replacement: Once the faulty component (e.g., a shorted capacitor, a leaking IC) is identified, it needs to be replaced. Carefully place the new daughterboard into its housing, ensuring it sits flush and aligns correctly with any screw holes. Swap SIM Card (if possible): If you have another 5G-compatible phone, try inserting your SIM card into it. While the latter is ideal, even an entry-level thermal camera can provide significant diagnostic advantages over traditional methods. Even a few feet of vertical movement should show a small, measurable change. Insert Pry Tool: Once a tiny gap appears, insert the thinnest plastic pry tool or guitar pick you have. For lead-free solder (common in modern smartphones), a temperature between 320°C and 380°C is typically required, but this can vary based on the specific solder alloy, board thickness, and preheater temperature. Damaged Display Connector on Board: Replace the connector or repair individual pins/traces if possible. Low Temperature Bonding: Requires lower temperatures than typical solder reflow, reducing thermal stress on delicate flex cables and display components. Align it precisely over the pads on the logic board, ensuring its orientation matches the original (this is where your reference photo helps). Random Reboots or Freezes: The phone unexpectedly restarts or locks up, often without an obvious cause. A slightly misaligned or partially inserted flex is a frequent cause of "black screen" or "no camera" issues.

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