Chosen Solution

I have a Mac Pro 6,1 2013 which turns on for a few seconds, then turns back off, where do I start with diagnosing the issue?

Sounds like a Failed Logic Board :( Part: https://www.thebookyard.com/product.php?… (UK) https://www.ebay.com/itm/284584975952?mk… (US) Guide: Mac Pro Late 2013 Logic Board Replacement