Apple Pencil (1st gen) stopped working on iPad Pro 10.5 (5th gen)

A couple of issues with your post here.

1. The iPad Pro 5th generation is not compatible with the First generation Apple Pencil, so it never would have worked.
2. The iPad Pro 5th generation is either 12.9" (2021) or 11" (current 2024 model) but not 10.5".
3. The 2021 5th Generation 12.9" iPad Pro is compatible with the Second Generation Apple Pencil or the Apple Pencil USB-C. The current 2024 11" 5th Generation iPad Pro is compatible with the Apple Pencil Pro or Apple Pencil USB-C.
4. The iPad Pro that has a 10.5" screen and that is compatible with a First Generation Apple Pencil would be the 2017 iPad Pro, and is an only generation. There was no other generation of that iPad Pro.

click here ➜ Identify your iPad model - Apple Support

With that said, if it is a 2017 10.5" iPad Pro, check a few things.

1. The Apple Pencil tip is firmly screwed into place

2. Restart the iPad. click here ➜ Restart your iPad - Apple Support

3 Update the iPad to iPadOS 17.

click here ➜ Update software on iPhone, iPad, or iPod touch in iTunes on PC - Apple Support

or here ➜ Update your iPhone, iPad, or iPod touch with the Finder on Mac - Apple Support

User651 wrote:

1. Hi!

Oh, you're right, my bad...

Yes, it is iPad Pro 10.5 2017 (seems 2th gen).

Yes, firmly screwed.

2. Already tried, didn't help.

3. I'm afraid to update it to iPadOS 17, it will become laggy.

Maybe there is another solution, without updating iPad?

Not that I know of. It should not become laggy though. But it's hard to say whether updating would actually help with the pencil. You should still consider updating if only for security. As the current update patches some important vulnerabilities.

Test the pencil on another compatible iPad if you can borrow one from someone and make sure it still works. Its possible the pencil has failed.