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Old School 5.25 Floppy Cable - without the twist.

redjr

Experienced Member
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Sep 29, 2021
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I'm trying to get a NorthStar clone controller up and running with my Sol, and I'm in search of a 34-pin floppy cable. Back in the day floppy cables didn't have that twist in some of the middle wires, but all the ones I've seen on eBay have it. That type of cable won't work with older controllers/drives will it? If not, does anyone have a link to such a cable available today. I'll keep searching...

Rick
 
Well, if the cable has connectors for two drives, and you only need to hook up one drive, you can connect the drive to the connector before the twist.

Depending on the connectors used, you might be able to remove the back of the connector, disconnect the twisted wire, and reconnect it non-twisted.

Flat 34-pin connector cables were used for lots of other things too. A middle ground between making your own from scratch and band new might be finding a long cable with two connectors and add a third ripped from a twisted floppy cable.
 
The point of the twisted cable was that drives "off the shelf" could be set to DS1 (second drive select) and allow for individual control of drive motors. The price was limiting the support to 2 floppy drives per cable (not a big thing on the 5150, since there was originally room for only 2 full-height drives). Some AT-type floppy/hard controllers (e.g. Ultrastor, DTC) make use of some unused lines to get an extra select and motor control ability for a third drive, but the cables have two different twists.

Finally, at least on some DTC hard/floppy controller has jumpers to enable the traditional "flat" cable for up to 4 drives. There is a price to pay, however. First, all drive motors operate simultaneously and second, all drives must use a different drive select (DS0, DS1, DS2 and DS3).

It's not hard to fabricate your own cable from connectors and a bit of ribbon cable, BTW.
 
Note that cable doesn't have card edge connectors at all three positions. I don't know what a northstar needs.
 
The Northstar uses pins at the controller end.

FWIW, I’ve popped the clips on cable connectors to un-twist floppy cables several times and managed to do it without breaking them, so if you happen to have a suitable cable lying around it’s probably an option. But the price for the IEC cable is pretty reasonable, assuming it’s long enough.
 
I'm not sure what the Northstar clone controller is like , I have only used the original and its connector has pins, and with that one there is no guard plastic shroud around it for the key projection on some plugs. The right angle pcb pins sit close to the pcb surface, so it meant that for plugs that will fit on that, with the correct orientation for a drive connector, they have to have the central plastic projection shaved off, to clear the pcb surface. Then as they were, or with the plastic shaved off, in either case they can be accidentally plugged the wrong way around. They probably would have fixed this issue on a clone card, but I don't know. In any case, for the N* card, the plug, when plugged onto the card, has the correct orientation when the ribbon cable after it leaves the plug is directed perpendicularly away from the solder side (bottom side) of the pcb.
 
During "The Great Changeover" ;-), when 5.25" floppies were on their way out and 3.5" floppies on their way in, cables with all manner of combinations of edge and pin connectors were common. Those cables still occasionally show up on that $#%@ auction site we all love to hate. I have a cable that actually covers all the bases, with an edge and a pin connector in each of the usual 3 drive positions. Also common were small adapters that one could use to "convert" an edge connector to pin and vice versa. it was common to open a new 3.5" drive and find one included in the box. Those also show up from time to time.

OTOH, as was mentioned above, IDC connectors can be scrounged from old gear and reused if one is careful to go slowly and keep the force applied aligned and even so the connector doesn't tilt as the teeth penetrate the cable. The tools to perform this operation are also available but not strictly necessary.
 
That $5 one from IEC probably beats all the other options unless you have a well-stocked parts bin already.

This. Those 34 pin connectors used to be dirt common and cheap (you’d have a fair chance of getting them at Radio Shack), but, coincidentally enough, I recently had to buy some myself for a project and they’re harder to find these days. (I mean, sure, you can still get them but they’re not a corner store item unless you live near Anchor Electronics or something.) Also the price of ribbon cable by the foot in small quantities is pretty steep. If you can find a manufactured cable it may well be cheaper than doing it from scratch.
 
Counting shipping those connectors are almost $3 each, which is why the prefab cable for $7 looks like a better option to me, but, *shrug*.
 
I agree, if I need a 'special' cable and it's under $10, I'll buy it. I used to make my own cables back in the day, but I had a borrowed press made specifically for ribbon style connectors, and it worked like a breeze.

The cables that I need for my drive(s) have arrived, or on their way. Now if I could only get a copy of N* DOS, or CP/M that will boot I'd be in business. However, at this point I'm not suspecting my drives, or cables. It could be controller related. More testing needs to be done.

Bob Stek, another member here was kind enough to lend me a couple of drives and disks to try. But late last night it didn't look to promising. Hence the need for some backup cables, that 40 yrs ago I would have had on hand. :) Today, I'm also going to hook up the VSG dongle and try that. I'm a little confused on the VSG though. More reading to do. Will it transfer an image to a cold MSD, without anything else being on the drive? Or does it simply copy at a low level on the disk?
 
Bob Stek, another member here was kind enough to lend me a couple of drives and disks to try. But late last night it didn't look to promising. Hence the need for some backup cables, that 40 yrs ago I would have had on hand. :) Today, I'm also going to hook up the VSG dongle and try that. I'm a little confused on the VSG though. More reading to do. Will it transfer an image to a cold MSD, without anything else being on the drive? Or does it simply copy at a low level on the disk?

I'm a little confused, what is the "MSD" here? (Do you mean "MDS", "Micro Disk System", NorthStar-ese for the controller?)

The VSG, "Virtual Sector Generator", is a dingus that lets you use normal "soft-sector" floppy media with controllers like the NorthStar that were intended for "hard sector" media. The difference between the two is "soft" sector media has only a single "index hole" that's read once a rotation to provide a starting point for the controller to time how it's going to space out however many sectors of data it's going to write on a track of data, while "hard" sector media has in addition to the index hole that marks the start/end of a rotation a varying number (10 or 16, usually) additional holes that mark the start/end of each individual sector. Hard-sector media was essentially obsolete by 1980, although a few companies like NorthStar used it a little later than that, so it's practically impossible to find today. Thus why the VSG exists.

All the VSG does is based on the averaging the time-per-rotation of the index hole construct additional pulses to emulate the missing sector holes. It does *absolutely nothing* with the actual data transfer lines to/from the controller, it only adds additional blips to the index/sector sense line. If the disks you're trying to boot from are real hard sector floppies having the VSG inline will just mess things up. (I don't know if it detects this situation and disables itself, I'm assuming not. And obviously since all it does is manipulate this one sensor it doesn't do anything in terms of transferring disk images, etc.
 
Yes, I meant MDS. I did more reading and better understand the VSG dongle and what it does. I will still need the PC2FLOP software(downloaded) first, and then get my serial link working too.

Rick
 
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