Answer to: Why is my phone not turning on?Try entering Download Mode to see if the device is bricked, otherwise it is either a faulty battery, charging jack, charger or dead hardware (mainboard). To enter download mode: Press and hold: Volume Down button + Home Button + Power button If the device goes to download mode, it probably means the device is not charging for some reason. Verify the charger is known good and working and if it is, the phone needs servicing. I am unsure if the download mode key combo is correct for the SGS 4G model, but that is the key combo for the Galaxy S series.
Answer to: How to disassembly my HTC Desire HD (A9191)?http://www.beardeddonkey.com/home/commen...-040327 Guide with large photos and indicators for tearing down to remove main boards. Use plastic prying tools if you dont want little dent marks on the back camera flash cover. This model phone has a lot of little screws and parts that can be pulled out. Be very pedantic about keeping everything safe once pulled apart, dont let kids near all the stuff or you might lose pieces.