RK05 alignment - without alignment pack?

[Tom Gardner]

> Date: Thu, 10 Dec 2009 18:09:08 +0100
> From: Philipp Hachtmann <hachti at hachti.de>
> Subject: RK05 alignment - without alignment pack?
> To: General Discussion: On-Topic and Off-Topic Posts
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> Message-ID: <4B212B34.6070003 at hachti.de>
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> 
> Hi folks,
> 
> I took a "new" RK05 disk drive from my heap. After defoaming I powered it
> up. I soon realized that
> the position sensor's glass had fallen off. Can be glued back in place
> easily. But after that I'll
> most probably have a misaligned RK05.
> 
> The RK05 manual tells me how easy it is to realign the heads: Just load
> the alignment pack and...
> -- But I don't have an alignment pack :-(
> 
> Does anybody (best would be in Europe) have an RK05 alignment pack I could
> use?
> 
> Is there a known trick to do it without alignment pack? I have working
> drives and formatted disks handy.
> 
> 
> Best wishes,
> 
> Philipp
> ------------------------------
With a good eyeball and a careful hand u can align to data.  Since you have
what you hope are calibrated drives, I would try taking a formatted pack on
a good drive and writing 1F and 2F signals on alternate tracks, 2F on TK00,
1F on TK01, etc. (I don't know what the RK05 code is but 1F and 2F
translates to some repetitive pattern).  It is not necessary to do so on the
whole pack, just circa TK00 and someplace in the middle of the pack.

The analog signal will have a broad flat peak region as u move the heads
across the track, so u can either eyeball the center of a track or better
yet use a micrometer gauge to measure the region and then move it to the
center.  I'm not sure whether it is better to look at the entire track or
two sectors 180 degrees apart.  Depending upon the resolution of the
recording system, the peak of a 2F should be about 0.7 of the 1F, so it
should be obvious as u move across a track.  

Since you are liable to be several tracks off, the first thing you have to
do is find Track Zero, which should be where the 1F/2F repetition starts.

Once u get all the heads aligned at Track Zero, do it again at TK01 where
you should have a clear track center (1F surrounded by 2F).  Then move to
the center and look at the signal again.  You don't have to move the heads,
just apply pressure to the carriage and see if you are more or less
centered.

The acid test is then when u read the pack :-)

Tom