[SOLVED] I'm looking for TOSHIBA G920 repair guide or schematics (free) - Phones & Tablets Forum

Hi,

I'm hoping you can help me out with my TOSHIBA G920. 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.

@Deniz

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 TOSHIBA G920 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/863344/What+would+cause+my+camera+to+shut+off+suddenly
Take a look at comment #643
Also, this : https://xdaforums.com/t/need-help-for-nexus-7-2013-wifi.3263248/.
You can also check this video starting from minute 2:

The TOSHIBA G920 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 TOSHIBA G920 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 TOSHIBA G920 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 TOSHIBA G920 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/are-there-any-rumors-out-there-for-a-car-dock-with-wireless-charging.1971386/

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

LDS antennas are excellent for multi-band operation and can be tailored to minimize interference between Wi-Fi, Bluetooth, and cellular signals. Third-Party Apps: Certain apps, particularly those claiming to "calibrate" or "enhance" the display, can alter color settings. Carefully disconnect all flex cables and remove all components from the motherboard. Most importantly, after reinserting the SIM tray, perform a functional test of the phone's cellular capabilities. If software re-flashing fails to restore the baseband, the problem is almost certainly hardware-related. A multimeter is highly recommended for continuity testing and diagnosing the extent of damage. What makes repairing them particularly challenging is the trend of integrating tiny surface-mount components (SMCs) directly onto the flex itself, along with extremely fine traces. Its location varies by model, but it's typically found near the top or bottom edges of the device, or along the sides of the frame. Most phones require heating the edges (with a heat gun or hair dryer) to soften the adhesive holding the screen or back cover. Secure and Cure: Use clamps specifically designed for phone repair or rubber bands to hold the panel securely in place for several hours (4-6 hours minimum, 24 hours ideal) to allow the adhesive to cure. Foreign Objects: Dirt, dust, or moisture around the edges of the screen can sometimes bridge connections or interfere with the digitizer. Clean the motherboard thoroughly, especially around the PMIC, with IPA and a brush. Use isopropyl alcohol on a lint-free swab to remove old adhesive residue, then a dust blower to ensure no particles remain. It often leaves the device in an unusable state, stuck in a boot loop, or simply unable to upgrade to the latest Android or iOS version. Ghost touches are another peculiar symptom, where the phone registers touches that aren't actually happening, leading to apps opening spontaneously, settings changing on their own, or typing appearing without user input. It usually sounds like a tiny, persistent hum, buzz, or faint screech, similar to the sound of an old CRT television or a faint cicada. If it's too damaged or cannot be reshaped to sit flush, a replacement shield is recommended. Visual Inspection: Using a bright flashlight and, if possible, a magnifying glass, carefully inspect the inside of the USB port. Check for Software Updates: Ensure your phone's operating system is up to date. When triggered, it automatically turns off the display to prevent accidental touches from your ear or cheek (like muting calls or ending them prematurely) and to save battery life. If individual kernel/driver flashes don't work, or if you want to completely revert to a known good state, flashing the entire stock firmware is the most comprehensive solution. Always proceed cautiously, especially when handling delicate flex cables and the battery. The Display Assembly (Digitizer) is Faulty: This is the most common outcome. Status Tags: Label parts as "New," "Used," "Defective," "Warranty Return," etc. Download Full OTA: Download the full OTA package for your specific device model. Causes: Loose connection, partial damage to flex cable, slight corrosion, software issue. Uninstall: If the problem persists or it's an app you don't frequently use, uninstall it. Restart Phone: A simple reboot often clears temporary software glitches. If the Wi-Fi chip is shorted internally, it will often heat up rapidly and excessively, visible with a thermal camera or by carefully touching the chip with a fingertip (be cautious, as it can get very hot). Diagnosing a smartphone that gets hot in one specific area is a critical step in preventing further damage and ensuring user safety.

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