My Old iPhone 8 is on charge after being out of use for some time, But with it being a black screen it keeps showing the Apple logo but will not let me turn the phone on

Perform a Forced Restart on the phone. Follow the instructions very carefully, as this is a bit tricky. You may need to repeat this several times.

Force restart iPhone - Apple Support

There are only 2 possible results when you perform a Forced Restart:

1) The phone returns to normal operation.....or.....

2) There is a hardware problem....likely the battery.....with the phone that will need attention at the Apple Store (make an appointment) or take the phone to an authorized Apple Service shop.

You can find a list of authorized service shops in your area using the link just below:

Find Locations

Lithium Ion batteries do not deal well with being left without a charge for long periods of time. It's likely the battery will need to be replaced.

brandon-lee144 wrote:

Many thanks for your rapid reply,

im just curious as I’ve had the battery replaced twice already in my old iPhone 8 by a friend (who is a mobile phone repair technician) so not in a sense done by an authorised apple technician. So your response and also the fact that I have had those repairs makes me believe that it is more than likely a battery issue.

Thankyou for your response, I’ll try the forced restart with it…

will it be possible to do a forced restart of the device itself only shows the apple logo then screen goes black again?

many thanks

Unfortunately, your phone is now unsupportable.

Best to just recycle it and buy a new one.

Hello,

You can try to get a 'new' iPhone but less pricey in the Certified Refurbished, which is on the Apple website of your country in Store, for example this is the UK Certified Refurbished Products - Apple (UK)

will it be possible to do a forced restart of the device itself only shows the apple logo then screen goes black again?

Normally yes, but if the phone has been tampered with by an unauthorized person, then all bets are off. The technician that you used did not have access to a genuine Apple replacement battery or other genuine replacement parts.

Apple or an authorized Apple service shop won't look at the phone, so if you decide to keep trying to fix the phone, the work will have to be done by an unauthorized shop and unauthorized technician.