I just contacted to WD distributers in our region and got information that WD doesn’ t sell power supply units for PR4100 separately. In case if NAS owner will need to use both power supply sockets they should looking for any alternative manufacturers.
When I bought my WD drive and saw it didn’t come with the second power supply, I looked in the WD store and bought what appeared to be the matching model, 0G05969. When I saw this thread on the forums, I linked the WD Store item here. The shipment arrived today, the power supply itself was the exact same make, model, size, branding, exterior finish, wattage, voltage, and polarity.
What is different about the supply from the WD Store is the inner diameter is 1.7mm instead of the 2.5mm diameter. I’ve confirmed power supply compatibility with the one that came with my Intel NUC8i7BEx and have looked closely at James.G’s post (WDStaff) and have found a few potential options on Amazon (warning the ones marketed for the WD PR4100 do not all meet the technical speficiations). I’ve had better result searching Amazon for the specifications rather than the model name of the unit.
It was somewhat disappointing WD would sell a dual-supply capable NAS and sell a 90W Power Adapter Kit that is not compatible. This seems like a missed opportunity for WD and has been a frustrating end-user experience. I was happy to pay 2-3x more to get a supply directly from the vendor but am glad that my purchase of the power adapter kit came with the 30-day money back guarantee. I’ve already started the return process for the power adapter kit.
January 2022: still no replacement power supplies in the WD Store. I have been having power supply issues (2 or 3 times) since I setup my PR4100 in May 2021. For some reason, this power supply is difficult to find. The PS that came with my PR4100 is an APD (Asian Power Devices, INC)
Model DA-90J19. Finally found on Amazon.
Sorry. Currently I am using a pair of Dell OEM supplies PA-1Each is rated 20 volts 70 watts. They have been running continuously for about 2 years now without a blip. WD calls for a single supply 19.7 volts 90 watts. The plug size used to be fairly common, I worked for an E-recycler for 16 years before Covid so I had the pick of just about everything I needed including the PR4100. I might have a bigger supply in one of my junk boxes, HP and Dell used that jack, center pin positive. Hope that helps, sorry for the late reply.