That particular PSU is notorious for having various power issues. You can get it rebuilt to make it work better, but I recommend just sourcing a 400-5198-01 PSU from a New Astro City which is a straight drop in replacement. They turn up from Yaton on eBay from time to time.
The grey PSU will not run low powered boards like CV-1000 Cave stuff, Brezza Crystal Soft, etc.