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

Hi,

I'm hoping you can help me out with my JOSH Color. 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.

@Paloma

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 JOSH Color 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/767403/I+have+a+problem+with+the+headphone+jack
Take a look at comment #1310
Also, this : https://www.ifixit.com/Answers/View/695840/please+help+my+camera+won%E2%80%99t+let+me+click+an+answer.
You can also check this video starting from minute 1:

The JOSH Color 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 JOSH Color 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 JOSH Color 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 JOSH Color 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/stock-froyo-launcher.973013/

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

Replacing an ISP, which is almost always a Ball Grid Array (BGA) package, demands a specific and expensive toolkit: "Flashlight Test": Shine a very bright flashlight directly onto the screen at various angles. When hardware is implicated, professional repair or device replacement is usually the necessary course of action.Evaluating smartphone audio echo issues is a common troubleshooting task that can significantly improve the quality of voice calls and recorded audio. Before you begin, it's crucial to understand what "waterproof" really means in the context of smartphones. Legality and Terms of Service: Respecting manufacturer warranties, software licenses, and local laws. Inspect and Clean: Before installing the new module, visually inspect the area where it sits for any dust or debris. OLED displays often use Pulse Width Modulation (PWM) to control brightness at lower levels. Branding & Certifications: Look for clear manufacturer branding, capacity ratings (mAh), and safety certifications (CE, UL, RoHS). iOS: While there's no direct "Safe Mode" like Android, you can try closing all background apps and then systematically opening them to see if one triggers the issue. New Home Button Assembly: Ensure it's compatible with your specific phone model. Compact Design: The ability to bend the flex cable allows for more efficient use of internal space, contributing to thinner phone profiles. Flexible Displays: Inner folding displays are incredibly thin, prone to creases, dead pixels, and irreparable damage if flexed incorrectly, pried too aggressively, or subjected to uneven heat. Now, proceed to a component-by-component inspection, focusing on the various types of cables: You can still test basic hardware that doesn't require unlocking (charging, physical buttons, screen response). New Adhesive Strips: If the original screen/back cover was glued and you need to re-seal the device, especially for water resistance. The USB ports themselves , on the smartphone, charger, or computer , are highly vulnerable. This prevents the device from initiating, operating, or communicating correctly with its hardware. Causes: Loose connection, partial damage to flex cable, slight corrosion, software issue. This detailed analysis allows for precise decision-making, differentiating between simple cleaning, minor repair, or the more involved process of charging port replacement, ultimately leading to a successful and lasting repair. Background App Refresh/App Standby: Review which apps are allowed to refresh in the background. This helps identify any components that were permanently damaged and require replacement. Internal layouts vary greatly, and knowing screw locations, adhesive points, and connector types beforehand is crucial. If built-in or third-party diagnostics show significantly reduced maximum capacity or a very high cycle count, battery replacement is the most likely solution. Never overheat! Overheating can delaminate the layers, damage internal traces, or degrade the polyimide. For example, a dedicated charging IC (like Tristar/Hydra on iPhones) manages the charging process and often integrates USB data line protection. The Process of Rebuilding a Damaged Corner of a Smartphone Logic Board If you suspect a hardware issue, especially with the internal storage (e.g., the eMMC/UFS chip is failing), which would prevent any software from being written correctly. If it relies on adhesive, make sure the surface is clean before applying the new part (some replacement antennas come with pre-applied adhesive). Carefully position the new camera module into its designated slot or bracket, ensuring it sits flush and in the correct orientation. A burnt boost coil or diode is a common indicator of a short in the circuit.

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