Dan

This is a copy of another answer I gave today: Perhaps because your battery is dead. Check your charger plug-in module with another USB device to see if it is still working. If your plug-in is still working, check your cable for physical damage, such as a deep crimp in the insulation on the wire (which might indicate that a wire was broken inside), or a dinged-up male for the tablet. There are 7 pins in the charger cable, buried down in the slots on that 30 pin connector, and the other 23 slots are empty. You might need a magifying glass and a bright light to see properly. Even if you can't see any damage, a replacement cable is less than 5 bucks: buy a new one and see if it fixes your problem. Remember if your battery is very discharged that it might take a while for the power-off battery logo to appear on the screen.

If you mean a red rectangle all around your screen, this sounds like an android developer's option. It indicates that the main thread (the one that processes your keyboard and touch inputs) is busy. Developers use this to make sure that they are not monopolizing the main thread, which is a BAD THING TO DO. A virus or piece of bad software would not care about doind BAD THINGS, of course. Back up your tab, boot it in safe mode, delete the apps you've installed, and reinstall them one at a time, slowly, until you find one that misbehaves. You can do a factory reset if that doesn't work. Be sure to back things up first, though.

Perhaps because your battery is dead. Check your charger plug-in module with another USB device to see if it is still working. If your plug-in is still working, check your cable for physical damage, such as a deep crimp in the insulation on the wire (which might indicate that a wire was broken inside), or a dinged-up male for the tablet. There are 7 pins in the charger cable, buried down in the slots on that 30 pin connector, and the other 23 slots are empty. You might need a magifying glass and a bright light to see properly. Even if you can't see any damage, a replacement cable is less than 5 bucks: buy a new one and see if it fixes your problem. Remember if your battery is very discharged that it might take a while for the power-off battery logo to appear on the screen.

Thank-you.

I’ve got a flippi V8 and just on a whim decided to save myself some time for tearing it down.

The re-attachment of that first cable was a challenge, trying to wrestle the chassis, motherboard, and ribbon cable. I've written a short guide that makes it much easier, accessible here:

Re-installing the motherboard of the 3DS XL

During re-assemblhy, note that the peg between the joystick mechanism and the circle pad is rectangular, and must fit into the matching rectangular socket on the circle pad.

In my 3DXL, there was no IR board: the parts were installed directly on the motherboard.

I was completely successful, although it was rather harder than indicated. Took me about 2 hours.

The battery replacement is different than illustrated if you buy the iPhone 5s battery replacement kit from iFixit: If I bought a repair kit, I'd very much like to see it illustrated exactly. There is a good way to install the battery replacement kit that does not appear to be documented, which guarantees proper placement of the battery such that the power connector is in the right place. It would also be good to have a little more guidance up-front for treatment of the battery cable. It takes a little careful folding, and there's also a little routing of the antenna cable that needs mentioning.

The touch id cable bracket reattachment is a little glossed over. There are two tiny tabs on the socket that fit into two tiny holes in the bracket, and then you just snap it down the tabs and holes acting as hinges.