ok so... I rebuilt a Series 3 with a 1 tb hard drive (thanks to the amazing information in this forum!) about 5 months or so ago. Yesterday I got a boot loop- Almost there... and then back to Powering up. Switched over to the backup S3 (tiny hard drive) and ran the SMART scan overnight (big hard drive) and now it is powering up just fine. No clicks from the HD- all seems fine. Any suggestions as to what might have cause it? Did I miss a cap when I rebuilt the power supply? Is the HD going bad? Should I make a backup? I want to switch my cards back over to this one cause of the hd size but afraid it will freak out. Thanks in advance!