[SOLVED] I'm looking for LOGICOM Tab 134 repair guide or schematics (free) - Phones & Tablets Forum

Hi,

I'm hoping you can help me out with my LOGICOM Tab 134. 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.

@Kurt

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 Tab 134 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/713033/MacBook+Air+A1466+reinstalling+OS+X+Mountain+Lion+help
Take a look at comment #786
Also, this : https://www.ifixit.com/Answers/View/463537/I+can't+open+my+call+log.
You can also check this video starting from minute 4:

The LOGICOM Tab 134 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 Tab 134 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 Tab 134 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 Tab 134 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/maybe-joining-the-evo-4-clan.1097137/

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

Enable OEM Unlocking: Also in "Developer Options," toggle on "OEM unlocking." This option might be greyed out if your device is carrier-locked or if there's a specific activation period (e.g., 7 days for some Xiaomi devices). You can use clamps or rubber bands to apply gentle, even pressure for a few hours to allow the adhesive to fully cure. By following these steps carefully, you can restore your phone's appearance and functionality, proving that a shattered screen doesn't have to mean a shattered budget.10. The transition to lead-free solders presented substantial challenges, especially for miniaturized, high-density electronics like smartphones. Visual Inspection: Examine the microphone ports (usually small holes at the bottom, top, or rear of the phone). Spudger (plastic pry tool): For disconnecting flex cables and prying components. Isopropyl Alcohol (99% or higher): For thoroughly cleaning adhesive residue. Fortunately, replacing this specific component is often much simpler and less invasive than other smartphone repairs, as it typically doesn't require full device disassembly in many modern phones. Missing Screws: A completely absent screw is an obvious and concerning sign of misalignment or oversight during assembly/repair. Entry-level thermal cameras, often smartphone attachments or handheld units, offer sufficient resolution for general board scanning. DFU (Device Firmware Update) or Recovery Mode are their equivalents for deep software intervention. Wipe the area thoroughly with isopropyl alcohol and a lint-free cloth. If the new display functions perfectly during the temporary test, power off the phone and disconnect the battery. Check for HDCP (High-bandwidth Digital Content Protection) compatibility issues, especially when streaming protected content. Bootloader: Low-level software that initializes hardware and loads the operating system. Software Updates: Ensure your phone's operating system and camera app are updated to the latest versions. Depending on the severity of the scratch and the chosen repair method, you may need some or all of the following: Many touch screen issues are software glitches rather than hardware failures. Heat the chip evenly with the hot air station (similar settings as removal). The best way to deal with screen scratches is to prevent them in the first place: Wrong Capacitor: Using a capacitor with the wrong value (capacitance or voltage rating) can cause circuit instability or future failure. If the voltage exceeds a safe threshold (e.g., 6.5V for a 5V input) or if the current becomes dangerously high, the OVP IC will quickly disconnect the VBUS line, preventing the excessive power from reaching and damaging sensitive internal components, especially the PMIC and battery. Check Results: After running for a while, stop the application/video and check if the pixel has returned to normal function. Screen/Back Panel Gaps: If the device has frame separation, it's more susceptible to liquid ingress. The heat softens the adhesive holding the screen in place, making it easier to separate. Physical Blockage: Ensure the small microphone holes on the device's casing are not blocked by dirt, debris, or a poorly fitting case. A swollen battery is a clear indication of internal damage and gas buildup, making it a significant fire hazard. Use a heat gun or hair dryer on a low-to-medium setting to gently heat the edges of the back cover or screen for 30-60 seconds. UV Curable Solder Mask / Adhesive: A liquid, light-sensitive polymer (often green, black, or red) used to insulate and secure jumper wires (e.g., Mechanic UV ink). This is especially useful for inspecting solder joint integrity or PCB surface texture.

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