+1 on that. Have a look around this forum for a couple of SPX-90 threads that deal with power supply issues. Any piece of gear with an SMPS, that "kind of lights up but doesn't work", or "works sometimes..." or, "works but takes a while to turn on fully", or "was working fine for years, until I turned it off for a day or two and now it won't power up" are ALL symptoms of capacitor failure in these kinds of power supply.
Zimbel Audio Productions Ltd.
"Studio House Calls". Authorized Warranty service for Allen & Heath, Clear-Com, Drawmer, Soundcraft, SPL and Yamaha. Repairs and upgrades to analog audio equipment including: AMEK, dbx, Neve, Neotek, MCI, Soundcraft and more. Ask about our RF frequency co-ordination services! www.zimbelaudio.com