I purchased this one on Amazon in November 2021 after the OEM one started intermittently getting really hot and shutting my Drobo 5D3 down, and it's been great so far:

KFD 150W 12V AC Adapter for Drobo DroboFS, S, 5D, 5Dt, 5N, 5N2, 5C 5D3 5-Bay 4 Bay Storage Array Network Storage DR-5X-1P11 DAS Hard Disk Drive HDD NAS Charger Heavy Duty Power Supply