IDC cable pitch for floppy drive

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Pacman
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IDC cable pitch for floppy drive

Post by Pacman »

What's the pitch/spacing of the 34-pin floppy disk drive IDC cable?
It seems to be 2.54mm, but with an ageing eyesight I can't be 100% sure.

I need to replace the cable in my STe due to recasing, and am thinking about ordering a new one from Ali Express, except most of the cables are for PCs (twisted wires), so I believe the best solution would be to just buy a suitable lengthed IDC cable, and attach a couple of 34 pin female IDC connectors at each end.
By the way, what is the maximum length I can have the cable without causing issues?
STe | MonSTer with dual IDE-CF memory card adapter | NEC Multisync 1990SXi | ST_ESSC | RSVE | Link '97 | Sony HD floppy drive/AJAX controller | Exxos HD floppy module | Battery-backed Ricoh realtime clock module | Discovery cartridge | C-Lab Unitor-2 | C-Lab Export | C-Lab Combiner | C-Lab Steady Eye | C-Lab Human Touch | Unicorn USB

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rubber_jonnie
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Re: IDC cable pitch for floppy drive

Post by rubber_jonnie »

Pacman wrote: 21 Dec 2025 14:35 What's the pitch/spacing of the 34-pin floppy disk drive IDC cable?
It seems to be 2.54mm, but with an ageing eyesight I can't be 100% sure.

I need to replace the cable in my STe due to recasing, and am thinking about ordering a new one from Ali Express, except most of the cables are for PCs (twisted wires), so I believe the best solution would be to just buy a suitable lengthed IDC cable, and attach a couple of 34 pin female IDC connectors at each end.
By the way, what is the maximum length I can have the cable without causing issues?
Pretty sure the plug pitch is 2.54mm so a standard bit of header will fit into the plug. As for length I have a cable that's about 3 ft in length for one of my machines and it works fine with up to 2 drives.
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LarryL
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Re: IDC cable pitch for floppy drive

Post by LarryL »

The IDC header pitch is 2.54mm
But since the header has two rows, the pitch of the cable is 1.27mm
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Pacman
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Re: IDC cable pitch for floppy drive

Post by Pacman »

Thanks guys.
I'll just order a 1m cable (34 pins/1.27mm spacing) and a bunch of female headers (34 pin, double row, 2.54mm spacing) then, attach a header at each end, and if I find I need it shorter after having done the recasing I'll just snap on a third header at the desired length and cut the cable shorter after it (or leave it as it is if an unterminated cable like that won't cause any issues).
STe | MonSTer with dual IDE-CF memory card adapter | NEC Multisync 1990SXi | ST_ESSC | RSVE | Link '97 | Sony HD floppy drive/AJAX controller | Exxos HD floppy module | Battery-backed Ricoh realtime clock module | Discovery cartridge | C-Lab Unitor-2 | C-Lab Export | C-Lab Combiner | C-Lab Steady Eye | C-Lab Human Touch | Unicorn USB

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