Ohio Scientific Challenger 4P/MF

Hi Jeff, The OSI systems typically used an MPI B-51 5.25" floppy with a built-in data separator. You can use any other 5.25" SS/SD floppy drive if you build your own separator. The Aardvark Journal Vol. 2 #6 (scan at http://osiweb/osiweb in the Aardvark Journal section) contains a schematic for a data separator on page 4. The discrete component values aren't readable on that scan, but from another article, you need: 74LS121 chip 74LS38 open collector quad NAND 470pf cap between pin 10-11 of the '121 18kohm resistor and a 10k pot between pin 11 and +5V If you use the 74LS38 instead of a 7400, then pull pins 3,4 of the '121 high via a 1K resistor. I have a two-part PEEK-65 (thanks to Earl!) article on interfacing newer disk drives to OSI machines, which I will try to scan and put on the site this week. David --- JMeyer101(a)aol.com wrote: __________________________________ Do you Yahoo!? New and Improved Yahoo! Mail - Send 10MB messages! http://promotions.yahoo.com/new_mail