RN628 stuck at "Welcome" display during boot

I fought with this for a long time.  Had left it off for more than a day, tried rebooting with all the random combinations, multiple times (some people said it was intermittent), and with various combinations of drives plugged in (empty, only the first, etc).

Nothing there worked, so I decided to take it apart and check for anything bad.  A tiny bit of dust to blow out, and I reseated the memory.  Now it's booting as normal.  Haven't had to reseat memory in anything in the past couple decades.  Apparently the front display will show the welcome message even if no RAM is present at all -- no beeping codes, no flashing signals, nothing.  Not sure if it was the reseat of the RAM, or powering it on with none present and then putting the RAM back in that actually made the difference.  If anyone else has a similar problem and no warranty support (ugh), it could be something to try.