In my atari 1040 ST I have an epson SMD 400 that actually does not really resembles the pictures you find online, and on the board is instead marked SMD 480L so I believe the actual model is 480L. However funky markings aside, it has very likely a busted head as - after cleaning and servicing - when connected to a greaseweazle is completely unable to read any track on head 1... multimeter impedance readings are also very different between head 0 and head 1 (mostly open which is bad).
I will run some further tests but I think I need to look for a replacement, and of course smd300s and 400s being viable also for amigas with minimal mods are really pricey. I've found a list on this forum of compatible PC drives but I was wondering if there's a best / better fit in terms of dimensions as I'd really like to maintain original bezel and button … is there also list of models originally used on STs (SMD480L being one but I need to find the ones not used on amigas) maybe I get lucky on ebay?
note I don't want to replace the drive with a gotek as my objective is to keep it as original as possible (that's why I would like a potentially period correct drive in rather than a common PC even if it cost a few euros more - but not 50
)