Dear sikachu and dolbyman,
I think that I may have the same issue and found this useful post.
My fixed (100 ohm resistor to solve LPC clock issue in 2022) TS-251+ failed again a few days ago.
Sorry for the naive question but how did you manage to recover your DOM image from the failed TS-251+? You had a previous backup?
Also, the behavior of the NAS is rather weird as I see the green status light on when the NAS is off, then when I switch it on: (1) the green light diasppears, (2) I see the same led pattern that you described in your first post (3) it switches off by itself and starts over, before being stuck with the same LED pattern.
Any clue about what I should look at to try to make it alive again?
Many thanks in advance for your kind help.