External DVD in Optiplex 5090 SFF

I doubt a single USB port will power those desktop drives -- though there are slimline (notebook style) USB drives that will work from a single (or dual) USB cable, desktop drives generally draw too much power and need a direct connection to your system's power supply.

Your question is why the LG and Samsung desktop internal dvd would not work via usb 3 to sata adapter on the Optiplex SFF.

The desktop-size DVD drive 5.25” form factor are power-hungry and usually need both 12V and 5V power sources. The usb 3 to sata adapter only uses +5V power.

PS

I have always used Dell external usb dvd with my optiplex 7040/7050/7070 SFF via a simple USB 2.0 to miniUSB cable.  It worked great.  You can also have the SFF sit on its side to use the internal dvd in a more comfortable horizontal orientation. The Optiplex has 4 small rubber feet on the non detachable side panel designed for sitting down.

@redxps630​ Thanks for your response. Yes the USB to SATA adaptor has 12 VDC external power.

I have placed the Optiplex in its vertical position cause I have no much room available in my computer table. Even the shelf on top is full. Maybe I need to add an extension to the table.

@ejn63​ The adaptor has external power.

Are you able to eject the dvd tray and see a green light turn on in the desktop dvd when connected to Optiplex?  

When you says both dvd tested ok in another pc, did you also use the same usb sata adapter to do the test?

Just curious, what if you connect a 3.5” hdd to the usb sata adapter?  Does your Dell detect the hdd?

@redxps630​ Yes.Tested with SSD and HDD both 3.5 and 2.5.

I haven't seen Device Manager mentioned yet.  With a CD or DVD in the drive, go to Device Manager and update hardware if not already.

If you already tried that, you may need an actual external DVD drive.  The slim ones that run off just one USB aren't as fast as the externally powered full-size ones.

I used an external hdd enclosure on desktop before and it worked well. So OP pc can use enclosure to detect sata hdd, but not dvd. it is strange. I would try test the dvd w same enclosure again on another desktop. My experience with these older 5.25 HH dvd is that they can be funky. I have seen some that show up but do not read burnt cd, only reads genuine Dell dvd.  They are becoming like floppy disk drive as they age, not reliable. OP can also try a third dvd drive. It is an intriguing puzzle so far but OP does not yet want to give up choose the slim usb drive option out.

I'm a little bit late but just to let you know that I purchased another USB 3.0 to SATA adaptor and both the Samsung and LG are working just fine. Obviously the DVD drives drain much more power than the first Sata adaptor supplied.

Thanks for your responses.