TEC FD-50x drives - known issues?

Hi Guys, I've been trying to get the drives from a Nabu Cable PC working for the museum in Toronto who wants to put a working system on display... The drives are TEC FD-501, single-sided DD drives. Some time ago I posted a request for technical information on the TEC FD-503 drives in one of my Morrows, because one of them had failed - the 501 is the same drive, same board, just without the top head and connector/components on the board. I didn't find any information, and ended up abandoning the drive and installing a panasonic DD drive - unfortunately this isn't an option for this system without a fair bit of work, because the drives are contained in an enclosure just big enough for the drives, and connect to a board located directly behind them with 1" cables for the data connectors. The data connectors are on the oppposide side from all the other DD drives I have (of course - and I have a fairly good selection!). The drives also have a silkscreened "Nabu" faceplate which would be nice to keep for the display. Both drives have failed - It is not a configuration/jumpering issue, because they were working - also, I have the exact same system, disk box and drives, and mine work - they are jumpered exactly the same. I've tried cleaning the heads, checking for other mechanical issues, and replacing all of the electrolitics on the drive boards - I can't do much more without technical information. I did try connecting a panasonic drive (had to hold it out of the case to get the cables to go on), and it worked perfectly - the problem is definately the drives. After some looking, I managed to find another pair of identical TEC FD-501 drives - these came from a MSI disk box which had stopped working, and guess what - both of those drives do not work either (jumpered exactly the same as my working ones). That makes 5 out of 8 TEC FD-50x drives drives that I have come across in the past year which are faulty - does anyone know if there is a known issue with these drives? So, I'm looking for (in this order): - Technical information on the drives which would enable me to repair these ones. - A pair of working FD-501 (or FD-503) drives which I could swap the faceplates with to closely aproximate the "original" drives. - Any DD 5.25" drives which will fit. Only need single sided, but double-sided will work. With the drive sitting on the table facing you (connectors at rear), the data connector must be in the left rear corner with pin2 on top, closest to the centerline of the drive. Can anyone help? Regards, Dave -- dave04a (at) Dave Dunfield dunfield (dot) Firmware development services & tools: www.dunfield.com com Collector of vintage computing equipment: http://www.parse.com/~ddunfield/museum/index.html