Hi Dave, Roger, and Mike,
I have a PR 903 which is not compatible, and I know that the PR604 is compatible, with some slight variations,so the 804 should be the same, (I hope) but thanks for reminding me that they only take floppies and no SD card.
Roger, regarding the weight issue, my SD card is nearly full so when I transport the KN7 I take the card out and put it in my pocket. VOILA!!! amazing how much lighter it is. I commend the practice to you. (The same applies with the floppy but not so great a difference!!!!
My friend has the PR804, a Roland AT 900 and an Allen theatre organ (3 manual, 10 speakers $150,000 worth)but access is poor to take my 7000 so I may revert to the Roland if I have a problem
Ray

PS where is Audrey these days?