Rep: 131
4
2
Everything working normally but when screen locked won't wake up again.
Problem appears after small work to u3500.
The first problem observed, flash light not working
Second problem observed, screen won't wake up
So replaced by series, u3300, u4000, u4020
Es esta una buena pregunta?
Rep: 221.4mil
15
289
806
What exactly did you do to U3500 and what was the original problem? Is the phone recognized by iTunes?
When you replaced the Strobe, Chestnut and Backlight driver IC, did you probe the circuit to see if any of the voltage rails were missing or low?
While there's nothing wrong with a shotgun approach to troubleshooting, the challenge is when it doesn't solve the problem. Then you end up with a whole bunch of variables (was the IC properly installed, bad IC etc.) and it makes it difficult to move forward.
I would take a step back and see if the logic board will boot and is recognized by iTunes with nothing but the battery and dock connected. Then add one element at a time and address issues individually.
Fue útil esta respuesta?
U3500 reballed.
Yes, the phone recognised by iTunes, and everything working properly, except screen wake up, you lock the phone, after 2-3 minutes will not wake up.
I am thinking possible cause LCM _TO_CHESTNUT_PWR_EN but everything looks normal here (u4000) tested on diode mode.
Steps was:
1. Phone stuck in headphone mode
2. U3500 reballed (headphone mode fixed)
3. Flash light not working
4. U3300 replaced (not solved)
5. Screen wake up not working
6. U3300 removed (wake up still not working)
7. U4000 replaced (still same)
8. U4020 replaced (still same)
9. U4000 replaced again (still same)
10. U4000 removed, all rails tested (ok)
11. U4000 installed (still same)
I would also check the MESA POWER and MESA DIGITAL I/O sections on the schematic.
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