Adjusting Alignment of Shugart SA-800 Drives

Discuss construction, troubleshooting, and operation of the Altair 8800c computer

Adjusting Alignment of Shugart SA-800 Drives

Postby toml_12953 » February 22nd, 2019, 5:27 pm

I have two Shugart SA-800 drives hooked to my FDC+ board. Each drive can write to diskettes and read diskettes written by itself but I can't boot from a diskette in drive 0 (A to you CP/M types) if it was created in drive 1. I can do a directory on the disk in either drive but can't boot from it. I believe one or both drives is slightly out of alignment but only slightly since I can access most of the other data on the disk. It's also a possibility the problem is only with track 0 since booting is the only problem I can see. I have the SA-800 maintenance manual and an SA120-1 alignment disk but will have to learn how to use an oscilloscope in order to use it. Is there a program that lets you keep the drive running and will step the head in and out and set it to a specific track? That would be useful. I can write a utility to do that but it will be faster if I could use one already written.
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Re: Adjusting Alignment of Shugart SA-800 Drives

Postby AltairClone » February 22nd, 2019, 5:42 pm

Yep, sounds like an alignment problem. Fortunately, the 800’s are pretty easy to work on. AFEXER is the software tool you need here: ... oppy_disk/

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