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If we are dealing with multiple phones the one with the blank screen but with sound is a bad LCD this guild will help with that Samsung Galaxy S6 Screen Replacement and your replacement screen Galaxy S6 Screen The one with the red dot may be just a bad connection to the LCD try reseating the contacts. clean both sides of the connection with 90+% IP alcohol and a soft toothbrush . Check for bent pins or missing pins. The issue of not charging could be either a bad battery or the charge port . to replace the charge port follow this guide Samsung Galaxy S6 Daughterboard Replacement and a replacement port Galaxy S6 Charge Port or battery Galaxy S6 Battery Hope this helps
Could be all just bad LCDs. If it boots up with no display then it’s probably the LCD as they can just stop working after the phone gets dropped right after.
@stengfix That is a tall order. I’d suggest that you start off with one or two and ask questions specific to that one. If you want to get trouble shooting advice for all of them at the same time, this may not be the right forum for you. You do want to consider getting a good service manual so that you can do the trouble shooting. Update (03/04/2017) @stengfix for the one you changed the display, which is working, but is stuck at the battery charging symbol, I’d suggest a new battery. If a new battery is not working, troubleshoot from there. You have to have a known-good starting point. Otherwise you are chasing your tail and potential go down a rabbit hole. Here is a start for further troubleshooting should it become necessary after changing the battery.
