Andrew, At 12:13 AM 2/5/98 +1100, you wrote: FWIW if it's just an alignment problem you should be able to write data to a disk and read it back with no problem. But you will not be able to read a disk written on another machine. If you can't write data and read it back from the same disk then there is something else wrong. The head material on the very old drives wasn't as hard as the stuff they use now and it's possible that the heads are worn out. Yes and a way to set the drive to a specific track. Usually a special test box but the are utilities for the PC to do that. Perhaps you can connect your drive to a PC long enough to align it. If you have the pin out of the drive interface and you understand how the interface operates it would be easy to make a test box. In addition, you will have to know the specific procedure that your drive uses. Also the procedure usually requires an alignment disk with special patterns at specific locations. I don't know (but I doubt) that all alignment disks are the same. Basicly you insert the alignment disk, step the heads out to a specific cylinder and look at the *analog* data coming from the head(s). The alignment disk has a two SIN waves recorded on it that are 180 degress out of phase, one is recorded on each side of the alignment track. When you look at the output of the read amplifier, the two SIN wave will be superimposed over each other and should be the same amplitude. If the drive is out of alignment, one SIN wave will be greater than the other. You then have to adjust the head radially to equalize the SIN waves. If the head is out of position more than a few ten thousands of an inch, you will see only one SIN wave or none. Then you have to step the head in or out to try and find out in whickh direction the alignment track is on the disk. Once you find it you know which way to move the head so then you set the haed to the proper track and move the head to find and align the SIN ways. If you have a double sided drive you have to repeat this procedure for the other head. You need the drive information to know where the test points are to look at the read amplifier outputs. And you have to know which track(s) on the alignment disk contains the alignment pattern. Of course, this is the simple version and assumes that the track step distance is fixed so you only have to align the reads at one position. In some older systems you have to adjust the head position at several points in it's travel. I have an 8" one. What model disk drive is it? I have a manual for a Shugart SA 400 (5 1/4"). It's very similar to the Shugart SA 800 (8"). It doesn't have the alignment procedure but it does expalin how the drive operates and it may be helpful. BTW does anyone know what kind of 8" drives are used in the Intel MCS 80 developement system? I have four of those drives and I wonder if they're suitable for this? I hope so. I have to do all this with mine too. Good Luck. Joe

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