ST-506 hard drive emulation - test-drb@ccmp.vtda.org

26 Jul 2005

Hi
 I shouldn't be saying this because I'm not sure when
I'll be able to look for it but I'm almost sure I have
the schematics for a 5 Meg Seagate drive someplace in my piles.
It might be a month or so before I come across it.
 I, also, am almost sure I have a ST506 signal specification
booklet from Seagate as well.
 I'll do some digging soon but I'm not where the piles are,
except on weekend ( but not this next weekend ).
Dwight

...
 From: ard at p850ug1.demon.co.uk

> > Correct. Don't uou have at least one ST506/ST412-interfaced drive 
schematic?
...

 Nope, unfortunately not :-( I've got various manuals for bridge boards,
 which of course have the connector pin-outs in (and give some of the
 theory), but nothing for a complete hard drive (I suppose I'mactually
 surprised such schematics ever escaped the drive manufactuers to be
 honest, as presumably ST506/412 units were never supposed to be field
 servicable?) 
THe HDAs were not field-repairable, but the PCBs certainly were/are. 

The IBM PC series TechResf contain schematics of some such drives (which 
ones depends on exactly which version fo the TechRef amd which updates 
you have). I've traced out a couple more. In general these drives are not 
particularly complicated, although there may well be ASICs for things 
like head switching, motor control, etc.

I must get at least one of the latter diagrems to you ay some point.

-tony