R720 connector documentation wrong?

Dan Langille

Member
Jun 29, 2015
32
0
6
59
I think my CD ROM is being powered by the Tape backup power connector, not the Optical drive connector.

Either that or the documentation is wrong.

Using the server service tag, the documentation leads to page 129 of https://topics-cdn.dell.com/pdf/poweredge-r720_owners-manual_en-us.pdf

When I opened the chassis, the CD drive was powered by J_TBU. This becomes clear with the following photos, which are from my Twitter post.



The two-wire cable (pink, or is it red, and black) in the above photo are connected to the CD drive.

NOTE: Not clearly seen in the above photo is the unused SATA power connector which leads off to the right of the page under the CDROM.

When I trace back that two-wire cable, I find it connected here:



That is clearly connector # 5 from the diagram, which is labelled as J_TBU

The SATA cable shown here was connected to the CDROM.

Now can you see why I think the documentation is wrong?

What interests me about this is the discover of two potential power sources for two internally-mounted SATA SSDs: J_TBU & J_BP0. My next step would be finding the cable for J_BP0.

Opinions please?
 
Last edited:

Spartacus

Well-Known Member
May 27, 2019
764
302
63
Austin, TX
So I just installed nutanix on a R730 and my CD drive is wired to the same 4 pin power port (which is wired the same as the R720).
That 4 pin connector can work for the sata or tape drive, in my case with nutanix I unplugged the CD drive to install a sata DOM that uses that 4 pin connector for power as well and plugs into the blue slot. Unless you need to install a tape drive or secondary device, it doesn't matter which port is used.
 
  • Like
Reactions: Dan Langille

Spartacus

Well-Known Member
May 27, 2019
764
302
63
Austin, TX
It should handle 2 ssd with no issue, theres also this option for a single drive to replace the CD: https://www.amazon.com/Deyoung-Drive-Caddy-Adapter-PowerEdge/dp/B074SCPC5S

Something to note the internal SATA ports are sata II and 3gb/s so they wont run at maximum speed for SSD, your better option might be a PCIE SSD.

If you could pick up a R720xd those are awesome, they have two 2.5" slots in the rear and 12x 3.5" (or 24x 2.5") in the front.
 
  • Like
Reactions: Dan Langille

Dan Langille

Member
Jun 29, 2015
32
0
6
59
SATA port speed was not something I had considered in my plan.

The ports will be used for the OS only, not for data. Most of the writing will be via the recently installed HBA.

Thank you for this information. Much appreciated.
 

Dan Langille

Member
Jun 29, 2015
32
0
6
59
I have another R720 which will undergo the same modifications.

The one bit of information to put out there:

The SATA power cable to the CDROM is split. The spare power connector it not clearly visible. It is under the shelf upon which the CD-ROM sits.

From the photo below:

  • power - the end of the cable attached to the M/B
  • CD-ROM - connected to the CD-ROM
  • spare - under the CD-ROM shelf
For this photo, I have disconnected the power cable from the CD-ROM and extracted from the cable from the cable channels at the side of the chassis.

In order to power the two internal SSDs, all I need is a SATA power splitter. No special cables required.

This solution loses power to the CD-ROM. I am OK with that.

IMG_1157.JPG