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Date   : Tue, 12 May 2009 16:32:12 +0100
From   : mike@... (Mike Tomlinson)
Subject: My Rodime Wont Spin

In article <COL116-W53B22E65A961A74DF5D4B887600@...>, Julian
Stenning <julian_stenning@...> writes

>    The drive has always been very noisy with the bearing/motor 
>    sounding 'dry', and now it seems its too stiff to spin. I can turn 
>    it manually, but that's not enough to get it going. Has anyone had 
>    experience of dismantling & servicing these things, or is it a 
>    bin-job?

Is it an old full-height 5.25" monster, or one of the later 3.5" drives?
(probably one of the latter as you say it's a Rodime.  What model is
it?)  They are prone to "stiction", where the heads adhere to the disc
surface and prevent it from spinning.

First thing to check is that the power supply is putting 12V on the
yellow and black wires at the back of the drive.  Do this with the drive
connected and disconnected; if there's any significant difference (e.g.
the PSU measures 12v off load but anything below 11V on-load), the PSU
has failed.

If that's in order, the next thing is to try giving the drive a sharp
twist in the same plane as the platters while applying power. Obviously,
be aware of exposed mains connectors, etc.  Don't bang or thump (or
drop!) the drive.  What you're aiming for is to get the platters unstuck
and rotating, then hopefully the motor will kick in.

This isn't risk-free, as if the drive has been unused for a long time,
the head(s) may have become well and truly stuck, and a successful
attempt to get it spinning may, uh, forcibly remove said head.  If that
happens, it's thank you and goodnight.  I would get the drive fairly
warm (in the airing cupboard, perhaps) before trying this in the hope of
softening the material that is causing the head to stick to the platter.

>    Lastly, I do have an old Western Digital MFM 30Mb 'FileCard' drive 
>    (rescued from an old Amstrad PC1640) that spins up when connected 
>    to the Acorn winchester PSU and adaptec board, but Superform wont 
>    complete a format. The drive parameters on the unit read 'H4, Wpc 
>    783, Cyl 782, LZ 783, Spt 26'. Can I use this?

Yes, you can use that drive, but not with Spt=26, which is RLL, unless
you have the RLL version of the Adaptec board (rare).  Assume for now
that you have the MFM version. Use Superform with the following
parameters:

Cylinders/CYL 782
Heads/HDS 4
Sectors per track/SPT 17

I can't recall if Superform allows you to input write precomp and
landing zone parameters, but if it does, use:

Write precomp cylinder/WPC 783
Landing zone/LZ 783

If you can't complete a format with those figures, the drive is probably
toast.

-- 
(\__/)   
(='.'=)  Bunny says Windows 7 is Vi$ta reloaded.
(")_(")  http://imgs.xkcd.com/comics/windows_7.png
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