Rodime 552 interface? Has 26 pin IDC connector.

[trag]

Does anyone here know what type of interface the ancient Rodime 552 hard drive uses? The connector on the drive is a 26 pin socket (standard .1" pin pitch, two rows of pins, etc.). These old drives are 20 MB capacity.

I'm hoping it is an adaptation of a common standard such as MFM (ST-506) or SCSI but with most of the GND pins combined into one or a few. Those 26 pins also apparently include the power pins as there is no separate power connector.

Any helpful or humorous comments would be appreciated.

 

[Buck]

Isn't that Apple II SCSI?

 

[Prof.Wizard]

Welcome aboard SF,
I guess this question can only be answered by our hardware paleontologist, Mercutio. :wink:

 

[Mercutio]

I'm basically a PC guy, Prof.

It ain't Apple SCSI. IIRC It actually used the Apple (II) floppy interface.

 

[Mercutio]

Well, it ain't Apple II Floppy, either. Those were 20 pin.

Where the hell is Tannin?

 

[iGary]

Does anyone here know what type of interface the ancient Rodime 552 hard drive uses? The connector on the drive is a 26 pin socket (standard .1" pin pitch, two rows of pins, etc.). These old drives are 20 MB capacity.

It depends on how you define "ancient." I've used 8-inch monstrosities from Imprimis and Seagate before Rodime existed.

I'm hoping it is an adaptation of a common standard such as MFM (ST-506) or SCSI but with most of the GND pins combined into one or a few. Those 26 pins also apparently include the power pins as there is no separate power connector.

Any helpful or humorous comments would be appreciated.

As far as Rodime hard drives go, I've used several external SCSI models quite some time back (10 MB, 20 MB, 40 MB models) on early Macintosh systems as well as PC-AT systems. However, they all used the common 50-pin IDC (two 25-pin rows in parallel) because they were SCSI. Rodime (a Scottish company, as far as I knew) primarily sold hard drives for Apple systems in their beginnings.

In your case, it sounds like this could be one of the interfaces that Apple and others devised for use on the Lisa, the original Macintosh, the Apple III, or some Apple II boxes. I've used hard drives on Apple III systems that had serial or Centronics parallel data interfaces. There was also a short-lived weirdo Apple interface that was neither ST-506 nor ST-412 (Seagate Technologies proprietary interfaces) -- but similar. I think it may have had a 40-pin or maybe 36-pin IDC connector like ST-506.

 

[trag]

In your case, it sounds like this could be one of the interfaces that Apple and others devised for use on the Lisa, the original Macintosh, the Apple III, or some Apple II boxes. I've used hard drives on Apple III systems that had serial or Centronics parallel data interfaces. There was also a short-lived weirdo Apple interface that was neither ST-506 nor ST-412 (Seagate Technologies proprietary interfaces) -- but similar. I think it may have had a 40-pin or maybe 36-pin IDC connector like ST-506.

This is probably the right track. This drive mechanism is found in the old Apple Hard Disk 20. The AHD 20 is an external mechanism which interfaces with the original Mac through the floppy port. It predates the Mac Plus which introduced SCSI to the Macintosh line.

Inside the external enclosure for the AHD 20 is a substantial circuit board between the data cable (floppy cable) and the hard drive mechanism. If the hard drive mechanism simply had an Apple floppy interface, I would not expect it to need so much logic on the separate circuit board. So my guess is that the circuit board translates between the Apple floppy interface and whatever language the Rodime 552 speaks. But that still leaves the interface of the Rodime 552 unknown.

 

[Mercutio]

Adaptec PCMCIA SCSI adaptors use a 26 pin interface.

 

[Tea]

Yeah, where the hell iz Tannin?

 

[Will Rickards WT]

Playing with his new toy?