my apple iphone 6s has black screen of death and wont switch on or charge what can i do?

Yes, you can. It probably is charged and on, the screen is just not responsive. Just hold down both the lock and the home button. Also a good way to check if it is the screen and that the phone is turned on is by flicking your silent button on and off and feeling it vibrate. Vibrating will show that you phone is turned on still, just the screen is not responding. :-)

Try putting it in recovery mode:

If you can't update or restore your iPhone, iPad, or iPod touch - Apple Support

If that doesn't help you can try the same, but in DFU mode (a bit harder to get to):

DFU Mode - The iPhone Wiki

While in one of these modes, connect to iTunes. iTunes then will ask you to restore or reset your device. You can either restore it with a backup or reset it to factory settings (and even then put back a backup later on).

Hope it helps.

Same problem with my iPhone 6 which is 18 months old, just died in my hand, went to Genius Bar and tested phone and major hardware failure, £289 to swap phone!! spent hour on @AppleSupport and offered me a service for £296....on a phone they told me was dead....they do not care after they have taken your cash....

Have you tried simply holding the power + home button for about 10 seconds? It should show the apple sign and restart.

If that doesn't work try the above thing. And the fact it isn't showing any battery charging doesn't mean it isn't charging at all. Just try connecting it to a computer I guess.

Hi

Make sure your pc is running the latest iTunes 12.6.1

Connect lead to USB on your pc

Press & hold just the power button down on iPhone don't let go

Connect lead to iPhone keep power button pressed down until pc sees iPhone Then wait for restore you may need to do this more than once Before it works.

If it doesn't work make an appointment at Apple store For a battery check

Or contact Support.apple.com.

Cheers

Brian

Were you able to restore your phone? Cause I have the same problem and ITunes is unable to restore my phone.