Good luck on that. I have a Blitz machine (same basic dimensions) that I couldn't do a 90 degree turn in my landing to get down to the basement due to the depth of the cabinet. I ended up having to install another door to my basement that would give me a straight shot.

I believe your only option to move it upstairs (short of dismantling it) would be to ensure that you could move it up to the first landing, then carry it sideways to the 2nd without turning the cab, then carry it reverse the final flight. You will most likely need at least 4 guys since you will be lifting the cabinet straight up at points since you will have limited space to tip it.

I just measured and my Blitz cab is 27" width x 39.5" depth. The landing I was attempting is 41"x39"... I couldn't fit the machine through the door sideways nor could I fit the machine down the steps sideways and there wasn't enough room at the landing to turn the machine.