C128 Repair - Can You Help?

This C128 has a very strange fault and I need help from anyone that thinks they can help. Main Channel: Main Channel - https://www.youtube.com/@MoreFunMakingIt Discord Channel https://discord.gg/5fmPMzU More Fun Website https://www.morefunmakingit.co.uk/ My Twitterings can be found here https://twitter.com/morefunmakingit Ko-fi page https://ko-fi.com/morefunmakingit Amazon Wishlist https://www.amazon.co.uk/hz/wishlist/ls/I5EGNMXIW5PC?ref_=wl_share