The SD-90 is configured to use USB for MIDI input by default.

To change that, turn on the SD-90 and then press the SYSTEM button once it gets to the main screen. There press the Page Down button once, and rotate the leftmost of the three knobs to change the MIDI Startup option from USB to MIDI. Press ENTER afterwards to save the settings.

Something is wrong here. When I get to that screen I see that the three knobs control the MIDI, INST, and DEV ID. When I rotate the one on the far left for MIDI Startup I get no response on the screen nor does the middle knob for Inst. Startup change anything. When I rotate the DEV ID the value goes up but when I reverse the rotation it does not go down. Is any of that normal? I get the impression its not.

Upon closer inspection of the three selection knobs the two that do nothing when rotated are very loose and have no resistance at all when turned. The one on the far right has some resistance but very little. It looks like all three knobs are defective.

Now I have to look into the major hassle it's going to be to get a refund on this especially with it being a purchase from Japan. Not looking forward to this...

None of the behaviour you mentioned is normal, unfortunately.

The knobs should have some resistance and distinctive physical feedback when they are rotated in either direction. Some repair might be needed, but I don't recall any exact procedures.... :\

Encoder knobs, particularly ones designed to serve as primary interfaces on modules, can and do wear out over time. When rotated, you should hear a slight clicky noise and the aforementioned physical resistance that DX7_EP mentioned. It could be physical dirt/dust that is impeding them and so a good cleaning might help. Conversely they could need to be outright replaced.

Spent some extra time examining the encoder knobs. They are in really bad shape. The box it came in did not show any kind of damage so they either took a sharp blow during shipping or the seller sold it to me in defective condition. I still have not heard back from the seller so I doubt I am going to get a refund or at least covering the repair. Looks like the repair could be anywhere from $100 to $150. There is a Roland authorized service center just about 10 minutes away from me so I will take it down there and get it fixed.

Thanks for the responses!

How handy are you with a soldering iron? If you can figure out the specific part #'s, you can probably buy the replacements for a couple bucks apiece.

$100 to $150 to replace a few encoders quite frankly sounds a bit of a rip off.

I don't have the final quote on the repair but after contacting several places that can do these repairs they all have an evaluation fee/1st hour of labor of $80 to $100 and then after that its the cost of the parts. If the encoders are that cheap then I should only be paying right around $100 as I can't imagine it would take more than an hour to replace all 3 encoders.

My soldering skills are primitive at best so for an expensive device like this, I would prefer having a professional do it. If it's right around $90 to $110 for the repair+parts I could deal with that.