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Let's discuss 1.2 MB floppy drives, rebuild, repair, refresh, refurbish


Keatah

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The typical 1.2MB 5.25" floppy drive remains a pinnacle of an era long gone. They were the last widely adopted implementation of the 5.25" formfactor. One that screams vintage upon sight. They were reliable - especially compared against the 1.44MB 3.5" drive.

 

I recently spiffed up a number of Epson SD-600 drives. The one major fail point on this model is the black knobby sleeve that rotates with the "door close" lever. Its a high-stressed part that's made from plastic. It develops cracks and causes the flip-lever to not do anything. Aside from that, everything else seems well-built, over-built, heavy, as most vintage things are, compared to the shit made today.

 

Other nice little things were that parts seemed self-aligning. Anxiety dissipated during disassembly because most everything was notched and keyed to fit only one way. And in factory-set position. Like for example you couldn't mount the motor wrong or off-axis. Screws holding stuff together were pretty much the same size/type, ones that were sized different were obvious where they went. A regular screwdriver was all that was needed. Sector index & write-protect optical sensors snapped into place only one way. In a self-aligning holder socket. I'm sure there's a technical name for that - but I wouldn't know it and I don't give a shit either!

 

Other things I did to the drive was replace/refresh 30-year old lubricants, thorough dusting off, reseating/cleaning electrical contacts especially the ribbon cable contacts, cleaning the socketed termination/pullup resistor pack as it had condensation corrosion on it.

 

And of course the required scrub and oxy-bleach of the now-white faceplate. Wrapping it all up with a clean of the heads and complete operational test.

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I don't think I ever used a 1.2MB 5.25.   Used a CoCo as the main computer for way too long, and they could only support the 360k (there are stories of people getting them to work, but not without heavy modifications).  By the time I got a PC, 1.44 was the standard.

 

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Even 1.44 wasn't bad.... at first.  The biggest problem was when contaminants got into the disks themselves.  The plastic case and spring door were supposed to prevent that of course, but they didn't work well.

 

Early 3.5" disks were well made and lasted as long as a 5.25 was expected to.  But late in their lifecycle, well into the Zip drive era, they were made so cheaply that you could literally buy a box brand new and expect some of them to fail immediately.  Then Zip disks failed with the click of death, pretty much ending the era of magnetic media.

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Tandon made its sales on the basis of having cheaper manufacturing costs than the competition. That was the trick; cut costs as much as possible without causing failures within the warranty period. All the US 5.25" floppy drive manufacturers were out of that business by 1993. 

 

The early days of 5.25" high density disks had some issues since the original YE-Data drive could not read/write 360K floppies until IBM prevailed on floppy controller manufacturers to add the 300kbit/sec mode. The earlier 5.25" floppy drives had many failures like the wrinkling disks that reinforced hubs were created to solve or the excessive media wear that occurred with the double sided drives. The unusual 5.25" drives like the Apple Twiggy or Drivetec/Kodak 3 to 12 MB drives pushed the technology beyond what mechanical tolerances of the time could sustain. 

 

 

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Mmm technology being too advanced for its time. A problem back then. Luckily those were sub-technologies of a larger ecology. Just drives. And not the whole world of computing.

 

Never thought Twiggy would go anyplace. It looked too unconventional. Even scary a little. Especially to kid already familiar with handling thousands of standard 5.25" disks on the original Apple II (and other early micros). simply too much experimentation and untested tech.

 

On Apple II Shugart mechanisms I learned one of my first pro-tips. Lightly tap the door closed half-way only. Then close it fully. This centered the disk perfectly and gently. This actually applied to other-than-Apple drives. But I kinda practiced it anyways.

 

As far as 3.5" drives go, I had a lousy time with Amiga drives, and no improvement in the PC ecosphere either. They just sucked-a-dickus all around.

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  • 3 months later...

I work mainly with pre-PC computers from the mid to late 70’s. This is an era where 8” floppy drives were very common. The 5.25” HD drives work great as a drop-in replacement for 8” drives with a simple 50 to 34 pin passive adapter. While not quite as authentic an experience as with the 8” drives, they are much smaller, lighter, have simpler power requirements, are less expensive, and are easier to find then the big 8” drives.

 

Mike

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