Help my Identify this vintage 5.25 floppy drive 20-pin connector YL-55S1L

[gilmod714]

I just got this (like new) box of a vintage 5.25 floppy drive , but I can't find any info on it on the net .. it looks proprietary (perhaps NCR or some banking equipment or other ?!)

the model on sticker inside says YL-55S1L , it has a weird 20-pin connector .. I was able to reverse engineer and identify some pins as follows (but not all pins) ..

Gnd, +5, +12 , motor, index .. and not sure about DIR and STEP and the rest of the pins .. see photos below

.. I am also trying to find a way to connect it to a PC .. I was able to connect it to "Greaseweazle" and get the floppy to respond to spindle motor so far, but can not jog the stepper motor .. it tries to move initially .. but stops with error on GW

the head looks like it's "Double density" - single sided ...

The sad thing is , it looks like a brand new floppy (never installed) ..


Can someone please help me identify the pins to this floppy controller ?! .. and perhaps find a good use for it ?!

Thank you in advance ..

 

[Chuck(G)]

Normally, when someone says "5¼" floppy" and "20 conductor cable", my first guess would be an Apple II drive. The very sparse drive PCB would seem to go along with that suspicion.

 

[krebizfan]

The Disk II uses a 20 pin with similar connection values to what you deduced. https://mirrors.apple2.org.za/ftp.a...tation/hardware/misc/Apple II Disk Pinout.txt

I saw Chuck(G) had posted just as I found the link.

 

[Eudimorphodon]

Going to echo @Chuck(G) here, that's probably an Apple drive. A really important point about the Apple interface is those pins you identified as "step" and "dir" are *not* that, they're raw stepper motor driver phase lines. (These drives *also* don't have an index sensor, and your "motor" line Apple calls "drive enable"; essentially the same thing.) You might actually damage the drive if you muck about with those the wrong way.

In short you're definitely not connecting it to a PC disk controller, and I don't *think* Greaseweazle has Apple II drive support(?). There is a thing *like* a Greaseweazle specifically for Apple drives, the name of it escaping me at the moment.

Edit: Oh yeah, "Applesauce":

Applesauce Hardware and Accessories – applesauce

 

[gilmod714]

Thank you guys so much, I appreciate that ..

yes, the disk II interface looks like it! .. and I wasn't aware that Apple drives used a completely different controller standards, I never owned or used an Apple (old or new) ..

I guess i will not be able to use it for anything at the moment then, sadly...

much love

 

[Chuck(G)]

Well, if MCU programming is your passion, you could always program one to interface to the drive. Jim Sather's "Inside" books on the Apple II contain a large amount of detail.

 

[Eudimorphodon]

Well, if MCU programming is your passion, you could always program one to interface to the drive. Jim Sather's "Inside" books on the Apple II contain a large amount of detail.

It might not be that hard to make a fork of Greaseweazel that can handle the difference interface, but the drive is almost certainly just single-sided and between that and the lack of an index sensor it's going to be of pretty limited use. (I mean, obviously it'd be fine for reading Apple disks, and I don't *think* Commodore GCR floppies care about index pulses either, but if the Greaseweazel code relies on the index pulse for calibrating rotation speed or whatever it still might require software changes.)

 

[gilmod714]

Well, if MCU programming is your passion, you could always program one to interface to the drive. Jim Sather's "Inside" books on the Apple II contain a large amount of detail.

I would love to find a github project that already goes into that area using Promicro, stm32 or RP2040 .. I actually already had searched for similar interfaces .. the closest I found was fluxengine and adafruity floppy projects in general .. but it still needs lots of firmware tweaks it seems .. my GW was a DIY anyway with the "bluepill".. on a different note, I do also own a busted commodore 1541 drive (bad head) , If I could convert that drive into the 1541 , that would be a good use for it too! .. but I am concerned about the spindle motor IC-dirveboard not being similar at all.. neither are the motor wires ..

UPDATE: Jepler from Adafruit-floppsy had pointed me to some github posts were other people were asking the same-questions about DISK ][ drives .. and it seems possible that this drive can be used to read flux on the PC with some MANUAL pin modifications to the .ino sketch + an index sensor ... (unreleased hardware-prototype) !

Thank you guys! .. your replies had been tremendously helpful - not just in identifying the drive , but opened up doors for other new ideas too!

 

[gilmod714]

UPDATE:

finally, I was able to find a "good use" for this drive! by converting it to a C64 drive , to replace a "dead-head" in my 1541 unit

I posted my project details here: (to benefit others, desperately looking to fix their 1541) -- since those heads are impossible to find

Apple II disk ][ to commodore 1541 disk conversion (long board) : bks@ft : Free Download, Borrow, and Streaming : Internet Archive

Apple II disk ][ to commodore 1541 disk conversion (long board) This project was for converting an Apple II disk 2 drive to work with commodore 1541 disk...

archive.org

 

[gilmod714]

.. here's the final project working great with C64 - very happy with it .. thx everyone for the initial info , that kick started this mod in my head

 

[gilmod714]

.. here's the final project working great with C64 - very happy with it .. thx everyone for the initial info , that kick started this mod in my head

The link to the project details is also on Lemon64 :

** NEW 5.25 DRIVE MOD - Apple disk ][ ---> 1541 conversion !!!

I'm happy to announce and share my success in converting an Apple II disk II 5.25 drive to work in a 1541 ... it works great! I decided to post my project de…

www.lemon64.com