CDC 9429 Floppy maintenance manual

Chuck Guzis cclist at
Sun May 8 18:31:00 CDT 2016

On 05/08/2016 02:33 PM, Philip Pemberton wrote:

> My awards list more or less goes as follows:
> Hardest to align: Nintendo Famicom Disk System. For bonus points,
> when you replace the drive belt, you have to realign the drive hub,
> which sets the "start of track" position. There must be a jig or
> procedure to do this, but I've never seen it. Homebrew procedure is
> to loosen the hub and rotate it a few degrees until things align and 
> the drive works... The hub alignment, incidentally, is critical
> because the discs are written as a continuous spiral track, not a
> series of concentric tracks.

Used on the Smith-Corona PWPs as well.  Sad part is that the old belt
turns to goo and is hard to clean and get running again.  There is/was a
seller on eBay who was offering  polyurethane replacements.  I've got a
pile of those sitting in my freezer.

> Nicest half-height 5.25in: Teac FD-550 series I love these drives to
> bits. There are a bunch of variants (40/80 track, 1.2Meg and 360K)
> but they're pretty solid performers. Fairly good at reading crusty
> old disks. Keep a few Bemcot wipes and some isopropyl around to clean
> the heads.

I think you mean FD-55 series.  Shame that they never made any 100 tpi
varieties, but Teac did rebadge someone else's FH 100 tpi drive.

> Weirdest drive interface: the NEC 8-inch drive Uses something called
> a "VFO" interface (I think I remembered that right?), which is a
> Japanese standard. Also needs to be rejumpered to provide raw data
> output. This is jolly good fun, because the jumpers (if memory
> serves) have quite odd labels...

You can find old PC98-era Japanese stuff (along with some CNC gear) that
requires these.  Getting the gear going with a commodity legacy drive is
a real chore--there used to be a manufacturer of external PLL data
separator boards to accomplish this.

> The "What were they thinking?!" award: Amstrad 3-incher, made by
> Panasonic. PC style power connector pinout. With the 5V and 12V
> swapped. You can bet every one of these you'll find that's been
> "tested working, motor spins when powered but that's normal" will
> have a fried ASIC. Again, has a drive belt, but at least you can
> replace this without cocking up the alignment.

I've done in a 3.5" drive on a Joyce by thinking that nobody would be so
stupid as to swap the +5 and +12 on the same connector.  Yes, it fried
the drive.   Also, the interface cable requires some serious 'reweaving'
to interface to a traditional (Shugart-style) interface.

> For 3.5in PC drives, I quite like the Sony drives. From experience
> with DiscFerret, they're pretty good at pulling a clean signal off
> discs some other drives won't even read. Some Panasonic drives are
> better built, though. Apples and oranges.

I've lately taken up with Samsung SFD-321B drives for general use.
Well-made and very flexible.  I occasionally provide drives to the CNC
people where pin 34 is READY/ and pin 2 is DISK CHANGED/ with DS0 and
1.6MB (360 RPM) mode.  All easily done with the Sammies.

On a related note of "weird and wonderful", does anyone have media for
the Western Digital "Take Ten" cartridge drive?


More information about the cctalk mailing list