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kmpres
July 2nd, 2009, 08:39 AM
Hi Guys,

This is my first post.

I have a Northstar Horizon that is in need of a floppy head alignment. I did this once before some 25 years ago but have lost my Shugart manual and the schematics it contained. Do any of you know how to align these floppies, and perhaps more importantly, do any of you know where I can get an alignment floppy to do this task?

The computer is in perfect working order otherwise. I need to sell this machine as soon as possible. Anyone interested, or do any of you know of a venue I can use to sell it?

I also have a working Hazeltine 1500 monitor for sale.

Thanks!

Chuck(G)
July 2nd, 2009, 09:07 AM
Bitsavers.org has the Service Manual for the SA400 (http://bitsavers.org/pdf/shugart/39028-0_SA400_Service_May81.pdf).

Analogue alignment disks are still available, but freakishly expensive new. Perhaps there's a list member with one who will let you borrow one or you might find one on eBay.

Next to that, the best way I know of is to take known-accurate samples and adjust the alignment so that the samples reads reliably. You can also use an oscilloscope connected to the input of the read amplifier and adjust for maximum amplitude when using a known-good sample.

kmpres
July 2nd, 2009, 09:19 AM
Thanks, that was a quick turn-around reply! I used a scope, a home-made edge connector and the cat's eye test the last time I did the alignment. The system has been in storage in the US the past 15 years. I don't know if any of my remaining floppies are even readable, but I will travel to the States this month and may get a chance to test it out.

Thanks again for the info.

kmpres

Erik
July 2nd, 2009, 09:27 AM
Thanks, that was a quick turn-around reply! I used a scope, a home-made edge connector and the cat's eye test the last time I did the alignment. The system has been in storage in the US the past 15 years. I don't know if any of my remaining floppies are even readable, but I will travel to the States this month and may get a chance to test it out.

I have floppies twice that old that still read fine. :)

The best place I know of to sell that stuff is our very own Marketplace (http://marketplace.vintage-computer.com). A lesser alternative is, of course, eBay. ;)

Good luck!