I can't belive that the club of D9090 working owners can be so select ! Mine was dead for 5 years and took no more than 2 hours for it's resurection ...
I can assure that your web site helped me; not directly at the moment, but at least assuring me that it was possible ...
As far as I can recall, there had not been an enormous battle for it on eBay when I bought it ... and it made twice the travel from Germany to France as FedEx was incapable to put me a phone call to tell me it arrived !
Well, regarding ST225, as it was also fitted in MegaFile's Atari, I've salvaged quite a lot of them at the time, by just removing electronic board and turning by hand the plate engine that was stucked.
Regarding the electronics of the 9090 with a ST225, I simply added 3 metal spacers (didn't found a fourth yet) usualy used for "modern" PCs mainboards and the result is absolutelyu perfect.
That's very kind to you for the original copy of the user manual but I'm not so interested in "paper" collection ... it's the contents of the manual that would be of interest to me - Don't know it someone already scanned it for future generations.
I'll try to salvage the Tandon drive as I'm not sure if its fully dead or if something can be made for it - I do belive that something can be done (and may be find interesting stuff on it ?).
Regards - Hervé
PS : I'll try to run the test/demo program that searches for bad tracks & sectors ... I'll see if it works !