I have been looking for a 5.25" Floppy Disk Drive for recovering old disks. I wanted to make sure I got the right one and here i all of the notes on the drive I selected.

The Panasonic JU-475-5 will read all 5.25" disk formats so is a good choice and seems a popular choice.

• General Information
  • Floppy disk - Computer History Wiki - Diskettes, or floppy disks, were a popular medium of storing information in the 1970s up until the 1990s.
  • Floppy Drive Connector - The floppy disk interface uses what is likely the strangest cable of all those in PCs today. It is similar to the standard IDE cable in that it is usually a flat, gray ribbon cable. It is unusual in terms of the number of connectors it has and how it is used to configure the setup of the floppy disks in the system.
  • The bitsavers Homepage
    • The PDF Document Format - This section tells you how the guy scans his documents.
• Drive Information
  • drives:panasonic_ju475 [The Official Wiki for the Applesauce Floppy Drive Controller]
    • The Applesauce works best if the BX jumper is in place. This allows the controller to set the disk speed (300 rpm/360 rpm), which is crucial for writing and formatting double density disks correctly. BX does not usually come with a jumper.
    • By default, the JU-475-4 has the DC jumper set, but Applesauce may prefer having the RDY jumper set instead. (It still works fine with the DC jumper set, but may be faster with RDY.) This is the preferred configuration in the Alpha Microsystems manual linked below. 
    • This page has links to the relevant drive documentation on the bitsavers.org website.
  • Panasonic JU-475-5 - 5.25" Floppy Disk Drive | polyplay.xyz
    • Product page for a Panasonic JU-475-5-AEG
    • Has technical information on the drive.
  • Panasonic JU-475-5 - 5.25" Floppy Disk Drive | polyplay.xyz (WayBackMachine)
    • Product page for a Panasonic JU-475-5-AEG
    • Has technical information on the drive.
    • I have used the WayBackMachine because when writing this article the original site had a database error.
  • Panasonic JU-475-5 Product Sheet (Mitsubishi Electric) | actapricot.org
• Downloads
  • PANASONIC JU-475-4 SERVICE MANUAL Pdf Download | ManualsLib - View and Download Panasonic JU-475-4 service manual online.
  • Index of /pdf/panasonic/floppy | bitsavers.org - Panasonic floppy disk drive file repository.
• Mode/Speed Modifications and settings
  • DAVES OLD COMPUTERS - Modifying 1.2M drives for 300 rpm
    
    • Although 5.25" HD (1.2M) PC drives can read DS/DD media, they do so at 300kbps, which is non-standard for this media type, and has two disadvantages. (1) The disk images created will indicate a non-standard 300kbps data rate. and (2) it's hard enough to get a PC to read single-density - some that can do it at 250kbps cannot do so at 300kbps.
    • Fortunately, many 5.25" HD drives are fairly easy to modify to operate at 300rpm and 250kbps. This page describes how you can add a switch to a 5.25" HD drive to allow it to operate at either 300 or 360 rpm. The drive shown is a Panasonic JU-475 which is a very common HD drive used in PCs, however the techniques shown here can be applied to many other drives.
    • DAVES OLD COMPUTERS - Disk/Software Image Archive
  • Kaypro Hardware Part 2 | retrocmp.de
    • Panasonic, JU-475-5 AKO is mentioned
    • The special thing about the Panasonic and TEAC drives is that you can set the speed 360 or 300 RPM directly with a jumper. These are real dual-speed drives! Many other "dual" drives 1.2MB/360KB on the other hand rotate with constant 360 RPM and therefore write/read the data (for 360KB) with 300 kbit/s instead of usual with 250 kbit/s.
    • For this reason, you can use these regular "1.2MB" drives as true 720K/1M drives.
    • I forgot to mention that my Robie (now) has a Micro Cornucopia Pro-884 Max ROM. This can read and write all three Kaypro formats (200K, 400K and 800K) with a DS QD floppy disk drive (Panasonic JU-475-5: 2 sided, 96 tpi, 80 tracks).
• Cleaning
  • Cleaning and lubricating a Panasonic JU-475 5.25" disk drive - YouTube | Poking Technology - Does some basic maintenance on a 1990-ish 5.25" floppy drive. I have two, both of which failed in exactly the same way at about the same time, and after some time trying to diagnose and fix them (including replacing some of the capacitors!), it's been suggested that all the really need is cleaning and relubricating.... so that's what I'm trying.
  • Floppy Drive Lubrication \n VOGONS
    
    • So I just got my hands on a pretty dirty 5 1/4 inch drive , I was just wondering if I should grease the movement rail and stepper rail with lithium grease? Or would something like silicon grease be better?
      • I hear vaseline is good for lubricating ones floppy.
      • r would something like silicon grease be better? = yes
    • Okay so I cleaned the read head and lubed the rails , the drives not reading disks or formatting ?
      Is it possible the drive is a dud?
    • SHE LIVES! , hokay so turns out the drive wasn't cleaned properly , there was some brown crud on the read head and it wasn't coming off easily , I didn't want to damage the heads so I went pretty light on it first time around , this time though having nothing to lose , decided to do my best to get the crud off , it took alot of cleaning , to the point I was sure id damage the drive , but after putting it back in my pc it suddenly detected the drive was drive A instead of B for some reason so I had to turn swap floppies off. After that I managed to format and then write 2 disks , so it seems to be working now.
• Diagnostics
  • [SOLVED] Panasonic JU-475-4: issue with 5.25 floppy disk | VOGONS
    • When it tries to read a floppy, the head just moves back and forth a little and then stops, the "device not ready" message appears after that. The head movement is very short.
    • I cleaned the head with alcohol and lubricated everything. I can guarantee that the motor is working okay, I actually verified that by chance.
    • So first of all, these are 1-sided floppies. While most manufacturers made them all 2-sided by the time 5.25" drives got popular, and just branded as 1-sided, there is no guarantee they will work as such. Should though. And in any case these are double-density floppies and HD drives (such as your JU-475) can't write them very well. Sometimes it works, sometimes it doesn't, depends on the head and media (and contents). A HD drive should read a DD floppy though.
    • The extra hole would suggest these were used with something like C64 and flipped, if so you do need to reformat them. A PC FDC can't read GCR-encoded floppies. And if your drive can't properly write to DD media then these floppies will not be of much use as far as testing goes. But can still be used with 360k PC floppy drives.
    • To be sure if this drive works or not you need a HD floppy, and a known good one. So preferably not a NOS unformatted one. That being said, you mentioned a second floopy drive (3.5") that you have. Was it connected to the cable as well during testing? If not, connect it (make sure it has power connected as well) and try again.
    • As a rule of thumb if the floppy has an extra ring attached to the central hole, where the media is clamped to the spindle, it's a DD disk. Also that self-made write protect hole is a giveaway this particular floppy was used in 1-sided drive and flipped. So there is a good chance those are 1-sided floppies though yes, I can't be sure about that.
    • I just enabled floppy seek at boot, and now it can read the IBM DOS disks!
    • Formatted a C64 floppy as 360 kb one, first write was unsuccessful but tried again and it gone through. Read file back and was OK.