Looking for detailed info about the Amlyn 1865 5.25" 3.2MB floppy

[kengr]

I recently acquired an Amlyn Model 1865 5.25" half-height 3.2MB floppy drive, and was wondering if anyone here has a datasheet or any other detailed technical information about it.

I found this drive mentioned in the August 1984 IEEE MICRO Product Summary, where the drive was described as follows:

"Half-height 5.25-inch drive stores 3.2M bytes (unformatted) on a single UHR-II high-coercivity floppy disk. Track-to-track access time is under 2 ms, with buffered seeks possible. Data can be written in either FM or MFM coding with any soft-sectored format, since no embedded servo is used. Data transfer rate is 500k bits/s. $330 in 1000's".

I also found mention of this line of drives in an InfoWorld article (June 6, 1983, page 9), which discusses the "3.3MB" diskette technology.

In examining the drive, I found that it has a non-keyed 50-contact card edge connector, similar to card edges I've seen on 8" floppy drives. But in looking up the various 8" drive connector pinouts and examining the Amlyn 1865 card edge, it looks like the Amlyn pinout doesn't match any of the 8" drive pinouts I've found in my searches. It looks like all the signaling is done on one (lower) side of the connector, and the upper side contacts all appear to be tied together.

I would be very interested to find out more details on the pinout of the card edge connector of this drive, as well as any information about the controller card (I assume IBM ISA bus, based on the era), and the UHR-II high-coercivity media (which I assume is required to achieve the 3.2MB capacity).

Any pointers to more information would be much appreciated. Thanks!

 

[Chuck(G)]

For details on the Amlyn 50-pin interface, look to page 16 here.

 

[kengr]

For details on the Amlyn 50-pin interface, look to page 16 here.

Thanks very much for your reply.

What's confusing me, when comparing this interface diagram to the actual drive, is that the actual drive's pins appear to have all the even-numbered pins tied to ground, and the odd-numbered pins are used for signaling. The diagram states the opposite. Either this drive has a different pinout from the diagram, or the circuit board has the pin numbers mislabeled. The board shows pins 2 through 50 (even numbers) on top, and all of those pins are tied together. It's hard to see the underside, but from what I can see on the pins labeled 1 through 49 (odd numbers), all the signaling action is on those pins.

Anyway, thanks for this reference. It's a great starting point.