https://www.reddit.com/r/synology/comments/1ju91h3/a_blinking_blue_power_light_on_a_synology_nas/
To try, remove the drives. Does it start then ? If yes, it seems the power supply is in fact dying. Usually they die slowly, and initially can still power the mainboard without the drag from the drives.
https://www.reddit.com/r/synology/comments/1o0wkki/rs2418_dead_power_supply/
電源ユニットは徐々に劣化するので、HDDを外した状態にすると起動できる場合あり
RS2418+ 電源ユニット
EAN: 4711174729166
https://dnltrading.com/gb/synology/5197-synology-psu-500w-24p20p4p-power-supply-4711174729166.html
24p+20p+4p (24p マザーボード、20p バックプレーン)
https://www.reddit.com/r/synology/comments/16ywvu1/changing_power_supply_on_2411/
↓
Remark: This PSU is only suitable in 230V countries. Check our store for a 400watt PSU suitable worldwide (110-230Volt input).
...
RS2418+
And more...
This PSU replaces the following PSUs:
PSU 400_1 (EAN: 4711174729234)
PSU 500_2 (EAN: 4711174729289)
PSU 500_4 (EAN: 4711174729166)
230V で日本はダメ
https://www.ebay.com/itm/153015724839
変換アダプタ
https://poyu.co.uk/2020/07/13/making-the-qnap-psu-20-pin-sata-power-adapter/
