This helped me out a lot and I got my printer working again. Many thanks for posting this.
Before I found this post, I put a post on this site about the problem with mine and also messaged Creality through Amazon from where I bought my V3 SE as it is still under warantee (I bought it |Feb this year). I googled the problem and after looking at a few posts and then finding this one, this is the one I went with.
So, Bonfireman is a saviour and knows his business. Many thanks.