Drive disappears When powering on a 2nd drive - Power Supply Issue?

[soong]

This is a follow up from my other thread...

 

My setup is as follows: I have a SAS controller and a SAS expander. I have 4 of the drives in a trayless rack that I hot swap in and out for backups. I have 1 parity drive and 5 data drives. So if all 4 backup drives are in that's a total of 10 (spinning) drives (and 1 SSD cache drive)

 

Most of the time the following situation happens...

 

1) Insert Drive A, shows up in Unassigned Devices as expected

2) Insert Drive B

3) Drive A disappears

4) Drive B shows up

5) Drive A comes back, usually by itself within a few seconds, if not I have to pull it out and reinsert it.

 

I've tried the following:

 

1) I turned off all the other drives so this happens with only 2 drives in the system

2) Bypassed the trayless rack and same thing happens, so that doesn't seem to be the issue

3) Tried a different modular SATA power cable, same issue

4) If both drives are powered up and I plug and unplug the SATA data connectors everything works as expected, so it doesn't seem like it's a controller issue.

5) If Drive A is powered up and data is connected it shows up as expected. If I plug in only the power to drive B, Drive A disappears for a few seconds just like above. 

6) Also have intermittent issue with booting up with all the drives on - which again points to the power supply

So test 5 leads me to think the issue is with the power supply? I have a Corsair CX Series 750 Watt 80+ Bronze from 2016. I would think they would be more then sufficient for my setup? 

 

Any thoughts?