Path: utzoo!utgpu!water!watmath!julian!uwovax!42_145 From: 42_145@uwovax.uwo.ca (RIC WHEELER) Newsgroups: comp.sys.atari.st Subject: RE:Disk Drives (floppy and hard) Message-ID: <687@uwovax.uwo.ca> Date: 23 Sep 88 21:28:15 GMT Lines: 48 Organisation: University of Western Ontario, Canada WHEN I CONVERTED FROM SINGLE TO DOUBLE-SIDED DRIVES ON MY 520STFM I USED REGULAR IBM-TYPE DRIVES. I HAVE TWO 3 1/2" AND ONE 5 1/4"(FOR PC DITTO).I DECIDED TO MOUNT ALL THE DRIVES EXTERNALLY.THE THREE DRIVES ARE POWERED BY AN OLD IBM POWER SUPPLY WHICH I OBTAINED WHEN A FRIEND UPGRADED HIS PC TO A HEAVIER POWER SUPPLY. AS FAR AS HOOKING UP THE DRIVES,DRIVE ZERO WAS EASY.JUST EXTEND THE RIBBON CABLE FROM INSIDE AND PLUG IT DIRECTLY ONTO THE NEW DRIVE.THE PINOUT IS THE SAME.YOU WILL PROBOBLY HAVE TO REMOVE THE TERMINATING RESISTOR PACK FROM THE DRIVE AND I ALSO FOUND THAT I HAD TO REMOVE THE TERMINATING RESISTOR FOR THE DRIVE SELECT LINE WHICH WAS A SINGLE OHM RESISTOR.THIS MAY BE DIFFICULT TO FIND BUT IF YOU HAVE A TECHNICIATYPE FRIEND HE MAY BE ABLE TO HELP.IT'S QUITE EASY WITH AN OHMETER ON THE DRIVE SELECT PIN. FOR DRIVE 1 I MADE A CONVERSION CABLE FROM THAT FUNNY ROUND CONNECTOR TO A 34 PIN EDGE CONNECTOR.THE PINOUTS ARE AS FOLLOWS ATARI--------1--READ DATA--------------30------EDGE CONNECTOR 2--SIDE 0 SELECT-------32 3--LOGIC GROUND-----------ANY ODD NUMBER 4--INDEX PULSE------------8 5--DRIVE 0 SELECT---------10 6DRIVE 1 SELECT---------12 7--LOGIC GROUND-----------ANY ODD NUMBER 8--MOTOR ON---------------16 9--DIRECTION IN-----------18 10-STEP-------------------20 11-WRITE DATA-------------22 12-WRITE GATE-------------24 13-TRACK 0----------------26 14-WRITE PROTECT----------28 I HOPE THIS IS OF SOME HELP TO YOU. AS FAR AS GLUEING THE HEAD BACK ON YOUR ORIGINAL DRIVE,I PERSONALLY,WOULD JUNK IT.THE SLIGHTEST BIT OF GLUE BETWEEN THE HEAD AND THE GIMBAL WOULD MAKE THE HEAD RIDE AT AN ANGLE TO THE DISK,CAUSING TROUBLE.BUT THEN AGAIN MAYBE LESS TROUBLE THAN A LOOSE HEAD.YOU WOULD CERTAINLY NEED TO CHECK THE ALIGNMENT AFTER THIS DELICATE OPERATION. GOOD LUCK.