[Coco] FD-502 replacement drives

[Gene Heskett]

On Monday 18 December 2017 17:56:17 John Mautz wrote:

> Gene,
>
> The drives move freely and make the normal head movement noises.  I
> just get a ?IO ERROR when reading the disk. (Dir works on my 501
> setup).  I cleaned the heads as you described with same result.
>
> Thanks.

Humm, I wonder if the rosettes, the white nylon gizmos used to clamp the 
disk have collapsed from long storage in the closed position, which has 
been a problem for me when first using a drive I've not used before, and 
that would reduce the grip needed to spin the disk, and affect the 
auto-centering, which would allow the disk to run eccentrically. Are any 
of the disks showing damage such as a folded edge on the centering hole?

Looking at the rosette from the side, there should not be even a hint of 
the fingers folding back. The original idea was that they would be 
pushed in 2 or 3 thou such that its a tight fit within the socket of the 
spindle when closed.  But years of closed pressure against the outer 
flange face, which gradually bends them back to where the disk can seat 
off center a few thou. Since those are made out of pure unobtainium, 
theres not a heck of a lot that can be done.  Thats called "cold flow" 
and it would take 10 years worth of pressure in the other direction to 
put the correct 'spring' back into them. By now they have got to be as 
brittle as a glass tree ornament.

Another possibility is flea clip miss-programming on the drive. IIRC they 
can have the read channel enabled by the motor on, but since the motor 
on is usually a common to all drives signal, then the read from one 
drive might be swamped by noises from the other. They can usually be 
converted to read live when drive select for that drive is live. You 
might have to scour the net with google and see if you can find a chart 
of what jumper is what for those drives. For double sided drives, you 
may have to replace the controller to drive cables drive connectors with 
connectors that don't have missing contacts like the shack cables did.

When changing clip positions, make sure that all motors still run because 
neither the stock SS controller driver or any of the os9/nitros9 drivers 
have a spin-up delay when changing drive targets to cope with drives 
that are shut down and then restarted again.

> On Dec 18, 2017 5:44 PM, "camillus gmail" <camillus.b.58 at gmail.com>
> wrote:
>
> Hi Gene,
>
> Are you looking for the 5.25 drives, or the smaller 3.00 inch drives?
>
> I have two of the 5.25 drives and to be honest can't use them because
> I do not have any floppies anymore...
>
> If you send me 1 floppie I can test them, and maybe we can swap.
> I need a 512 triad memory upgrade, which I believe is sold by Mark
> Marlette for $50.00.
>
> Let me know if interested...
>
> cb
>
> On 12/18/2017 2:24:31 PM, Gene Heskett <gheskett at shentel.net> wrote:
>
> On Monday 18 December 2017 14:27:13 John Mautz wrote:
> > Hello,
> >
> > I have had two FD-502 enclosures for a few years now and when I
> > installed them today, neither drive worked. I do have and FD-501
> > with 2 drives and it seems to work (I don't have a lot of disks to
> > test with). I would like to restore my FD-502 to a 2 drive system in
> > working order. Why, because the drives are supposed to be double
> > sided.
> >
> > Anyone have 2 working FD-502 drives they would be willing to part
> > with?
>
> Are you able to remove the drives?
>
> If so. you will likely find the lubricant on the rails the head
> carriage slides on, a dried up caked mess. Clean those rods with paint
> store alcohol and put a thin film of vasolene or similar very light
> grease on them again. If the motor to head carriage connection is a
> very thin steel tape, it wouldn't hurt to clean it also as an old film
> of cigarette smoke will change its diameter enough to miss track on
> the inner tracks. If the motor is on the rear of the drive and has a
> long screw shaft, clean the gunk out of the groove in the shaft, and
> recoat with vasolene, ditto the tracking wire and the bronze leaf that
> serves as the drive nut. All this needs to be clean and lubricated.
> Quiet, you can't alway hear them stepping drives, are surefire signs
> the drive is due for a clean and lube job. The noisy drive is the one
> thats stepping accurately from track to track.
>
> While you have access, wet a q-tip and run it between the head faces
> to clean the heads. If any color comes off on the q-tip, toss it, get
> a new one and "wash, rinse, and repeat" till the wet q-tip stays
> clean. But do not bend them for a better view. Just slip the wet q-tip
> between them.
>
> > or
> >
> > Anyone know of a good source to find replacement drives? (Mitsumi
> > Elec. Co. - D502).
>
> These are genuine antiques today, buyer beware.
>
> > Oh, and yes I have and email out to see if the SDC master (Zippster)
> > has any CoCoSDC's avail for sale.
> >
> > Thanks for the help.
> >
> > John.
>
> Cheers, Gene Heskett
> --
> "There are four boxes to be used in defense of liberty:
> soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
> Genes Web page
>
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Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>