drives added to 5D bays (2 & 4) not spinning up

Hi. I have a Drobo 5D, which I’ve been using for a few years, with three 3.5" seagate 4G disks in bays 1, 3, and 5. Previously, I have grown the array by simply inserting a new disk into an unused bay. But I have now tried 3 different brand new seagate disks in bay 2 and bay 4, but they fail to spinup/light up in those two bays. Note that the disks are the same exact model of disk that has been working successfully in the other bays.

With a flashlight, I have taken a photo inside the open bays, and notice that there is no power connection in the 2nd & 4th bays, although there is a yellow ribbon cable where the power connector would be, running up the back of the bays. I cannot see if a connector is present in the 3 working bays without removing a working disk, which I have not done yet. says “Up to five (5) 3.5″ SATA II/III hard disk drives or solid state drives (sold separately).” so I don’t see why bays 2 & 4 would only support 2.5" (not requiring separate power).

Anyone have any input into this problem? Can the normal sata interface (i.e. what the 2.5" drive has) supply enough power for 3.5" drives? If so, then there’s some other problem with the 5D that it’s not powering those bays.

hi, can i check if the working drives (in bays 1, 3, 5) are 3.5in drives
and are the ones that you are trying to put into bays 2 & 4, only 2.5in drives?

there may be some other ways to test the bays but i think the 5d can only take 3.5in drives.
(i may have have misunderstood when you mentioned 2.5 but if you have a moment to help clarify it would be cool)


I think you are confused about what the connectors look like.

The SATA and power connectors for 2.5 and 3.5 inch drives are identical. The SATA DATA connector does not supply any power at all, under any circumstances, regardless of the size of the drive.

in this photo:

the SATA data is the left hand socket, and the power is the right hand socket (note that they are touching and all made out of the same piece of black plastic).

This is taken from a differnet 5 bay nas, but these are the connectors you should see inside your Drobo:

Again, the connectors are touching each other, the left hand side of the connector is the data, the right hand side is the power.


types of connectors are for IDE drives… they are not applicable to modern SATA disks

If you are in doubt please power off your drobo, pull out one of the working disks, and have a look at the connectors there