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Alignment disk and procedure for 9114A - Printable Version

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Alignment disk and procedure for 9114A - aj04062 - 03-26-2013

Can anyone offer a source for the alignment disk and a procedure?

Re: Alignment disk and procedure for 9114A - Tony Duell - 03-28-2013

I have worked on these floppy drives, I am not sure if I did one specifically from a 9114A, but it's a 'standard' full-height Sony double sided drive.

Firstly, are you sure you need to do the alignment. Unless you have removed the stepper motor, you probably do not. I have replaced the head carriage assembly with one from a scrap drive and when I checked the alignment it was spot-on. Certainly removing and replacing the head carriage, spindle motor, etc will not affect the alignment.

Secondly, unless the drive will format,write and read a disk (that is a disk formatted on that drive), the problem is not alignment. Alignment affects the interchangeability of disks with other drives.

If you are _sure_ you need to do it, you need several things :

The schematics (from the Australian site)

A disk drive exerciser. You will have to make up a cable to link to
the 26 pin connector on the Sony drive (the higher spindle speed is not a problem). You could use a computer with some kind of TTL level parallel I/O to act as the exerciser, what you need to do is be able to turn the control lines on and off, issue head step pulses, etc

An analogue alignment disk, sometimes called a 'catseye' disk

A 'scope with differential inputs. Bandwidth is not that critical

A special tool to move the motor if the alignment is incorrect. This is a screwdriver-like thing with a pinion on it, it locates in a hole in the drive chassis and engages with the toothed quadrant on the stepper motor. You will not do it just by turning the motor. I didn't need this as the alignment was spot-on, if I had, I would have to make it (but then I have a reasonable workshop).

What you then do is connect the drive to the exerciser, connect the inputs of the 'scope to the differential outputs of the read amplifier, trigger on the index signal and load the alignment disk. Step to the correct track (normally given in the instructions that come with the disk) then look at the pattern on the 'scope screen. Adjust the motor position to get the 2 lobes the same size.