> On Mon, 11 Jun 01 11:57:55, [EMAIL PROTECTED] (Howard Schwartz) wrote:
>> I wonder if anyone knows how one goes about aligning what I assume is
>> the magnetic read head of a floppy drive?
Sam Heywood replied:
> I know a proprietor of a computer repair shop who is a friend of a
> a technician who used to earn a living at re-aligning floppy drives.
> He said that the job required extensive training and very expensive
> equipment. A very high level of mechanical skill is required to perform
> the critical adjustments and measurements.
When I did my hardware engineering training we had to make a box of
tricks called a disk exerciser. It was a peice of stripboard 6" X 4"
with 6 74 series TTL IC's, a cristal, a few resistors and capacitors etc,
a rotary switch, a 25 way ribbon cable and floppy connector and the wire
and plug to fit a floppy drive. We were given the circuit and had to
build it, after we had puzzled out the layout and wiring up.
Week's later I used the disk exerciser to align some 5 1/5 drives.
I connected up an osciloscope to the disk exerciser and I was given a
special alignment diskette. I think you did it on the middle track
(24) and after undoing the head adjusting screw, carefully moved it
until a circular display called "cat's eyes" was clear and uniform on
the scope. Then you tightened the screw. There was a button on the
exerciser that incremented the head one track each time it was pushed.
In practice as has been pointed out the service workshops don't bother
these days and dump the drive and charge for a new one.
>From what I remember the cost of the components to build the exerciser
was about 10% of the retail cost of a simular one from an electronics
supplier, but...the special alignment diskette was quite expensive
and very fragile, and of course you needed an osciloscope handy.
Bie LLP
-- Arachne V1.70;rev.3, NON-COMMERCIAL copy, http://arachne.cz/
