Looking for a SS 8" floppy drive

[glitch]

I'm looking for a second 8" single-sided floppy drive for my OSI Challenger 3. I've got it booting using a single drive, but the copy utilities for OS-65D are meant to be used with a dual drive system. I've got a pile of OS-65D floppies of various versions, but the only thing that still boots is the master copy of OS-65D V3.2. A second drive will allow me to build a working OS-65D V3.0 floppy and load the Extended Monitor without swapping bad floppies around.

It doesn't really matter what model the drive is. It does need to have an onboard data separator. I'm currently using a Shugart SA-800. If I could find another, or a pair of drives, that would be great since they're mounting one-over-the-other in the OSI chassis. Misaligned/nonworking drives are fine too -- I have AADs for 8" drives.

 

[MikeS]

I'm looking for a second 8" single-sided floppy drive for my OSI Challenger 3. I've got it booting using a single drive, but the copy utilities for OS-65D are meant to be used with a dual drive system. I've got a pile of OS-65D floppies of various versions, but the only thing that still boots is the master copy of OS-65D V3.2. A second drive will allow me to build a working OS-65D V3.0 floppy and load the Extended Monitor without swapping bad floppies around.

It doesn't really matter what model the drive is. It does need to have an onboard data separator. I'm currently using a Shugart SA-800. If I could find another, or a pair of drives, that would be great since they're mounting one-over-the-other in the OSI chassis. Misaligned/nonworking drives are fine too -- I have AADs for 8" drives.

It won't fit in the hole, but functionally a 5.25" 1.2MB HD drive could probably work for ya in the meantime...

 

[glitch]

It won't fit in the hole, but functionally a 5.25" 1.2MB HD drive could probably work for ya in the meantime...

I do plan on doing that conversion with the OSI, but I need a data separator. I'll likely build an adapter board with a 1-shot FM separator and interface converter when that time arrives. Make it generic enough that I can use it with my 4FDC even!

The OSI-470 floppy controller also doesn't make proper use of the drive select lines on the drives themselves. Instead, they send the select for the second drive on some of the auxillary pins of the 50-pin connector. You then cut the traces to DS0 and DS1, and jumper DS1 to whichever aux pin they use.

 

[dave_m]

but I need a data separator. I'll likely build an adapter board with a 1-shot FM separator

glitch,
I shuttered when I read "One Shot". I have never had good luck with those devices. They are too "analog" for their own good. Your bit error rate may be quite high.

If you have an appropriate clock available, there are much better ways to do the job with a counter and a PROM sequencer or some logic in a simple Programmable Logic Device.

 

[Chuck(G)]

A one-shot separator consisting of a 74LS00 and a 74LS121 can do a decent job on FM, but it has its limits. If you'd like, I've got some WD9216s and I suppose that I could part with one. 8 pin DIP, all you need is +5 and a reference clock (2, 4 or 8 MHz) and it does the job for you. It also does MFM separation, so if you ever wanted to go that route, you'd be in fine shape.

 

[dave_m]

I've got some WD9216s ....

Chuck,
Psshaw, too easy. Let the kid design his own.

Why do you ALWAYS have the right part for the job? Your parts bin must go from floor to ceiling.

-Dave

 

[Chuck(G)]

Chuck,
Psshaw, too easy. Let the kid design his own.

Why do you ALWAYS have the right part for the job? Your parts bin must go from floor to ceiling.

I never throw anything in the way of parts away, if I can help it. Before an appliance goes to the recycler, I'll pull it apart for useful things. You never know what you'll find in an old copier or TV. You never know when you'll need something...

But the 9216s are new. Back when a distributor was clearing out their old IC stock, I bought every last 9216 they had in stock.