I have around 75 of A1246 and 1166pros I bought this year. I have had nearly a 25% failure rate on the PSUs. The Avalons being sold this year are junk. So I've bit the bullet and bought a bunch of spare PSUs which has fixed most of the issues.

FWIW your blinking red light on the PSU itself definitely means the PSU has an issue. Usually if you keep running it it will eventual pop/fail and not run anymore at all.