*-*-*¢ The XF551 Enhancement¢ Review by David Bryant (GKAUG)¢¢ (Ed. While this is an old article,¢ (February 1989) I'm sure many of you¢ have not seen it, and even if you¢ have, it's valuable info, worth¢ reprinting, specially if you have¢ purchased an XF551 since the article¢ appeared. A.P.)¢¢ How many of you have taken your trusty¢ double sided floppy disk, punched a¢ write protect hole in the jacket, and¢ flipped it over to write on the¢ reverse side? If you're like me,¢ you've done it many times. So I¢ thought nothing about it when I got my¢ XF551 disk drive. I just put the disk¢ in and loaded those basic programs¢ like nothing was different.¢¢ I was wrong. The first time I went to¢ format a disk, (using Atari DOS 2.5)¢ the drive protested and gave an error¢ #173. I also had problems trying to¢ write to the back side of disk in the¢ XF551. I then got a gift from a¢ friend, a modification for the XF551¢ that allows it to operate like my¢ trusty 1050. Now formatting or¢ writing to the back side of disks is¢ no problem. This handy mod is called¢ The XF551 Enhancement, from Computer¢ Software Services.¢¢ If you look at a floppy disk, you will¢ see a smaller hole near the edge of¢ the large hole in the center. This is¢ the index hole and some drives use it¢ to tell when it is at the beginning of¢ a track. The 1050 does not, so when¢ you flip the disk, it doesn't matter¢ if there is no hole on the reverse¢ side. The 1050 uses a signal from the¢ RAM I/O TIMER chip to provide the¢ index pulse to the Floppy Disk¢ Controller chip.¢¢ The XF551 uses a index hole sensor to¢ provide the index pulse, and that's¢ where this kit is needed! After you¢ install this kit, a switch on the back¢ of the drive allows you to choose¢ XF551 or 1050 mode. In one position,¢ the drive acts like a standard XF551. ¢ In the other position, you can format¢ and write to the back side of disk¢ like the 1050. Also you don't have to¢ punch write protect holes in the¢ jacket anymore.¢¢ The kit consist of an epoxy shell with¢ the circuitry inside and a switch. ¢ About seven wires need to be attached¢ to the circuit board and write protect¢ sensor inside the XF551. Instructions¢ included with the kit are very easy to¢ follow. I would however remove the¢ circuit board from the drive (only¢ three more screws) when soldering to¢ the IP jumper location. I located the¢ switch above the Drive Select Switches¢ and the epoxy shell next to it inside¢ the rear cover. There's plenty of¢ room and everything goes together¢ easily.¢¢ I wish to thank Computer Software¢ Services for a good product. Current¢ cost is $29.95 and they will provide¢ installation to those without¢ soldering skills. They may be¢ contacted at:¢¢ Computer Software Services¢ 465 Kilbourn Rd.¢ Rochester, NY. 14618¢ Phone: (716) 467-9326¢ or¢¢ P.O. Box 17660¢ Rochester, NY. 14617¢¢ (Ed. David Bryant is a devoted ATARI¢ user, treasurer of G.K.A.U.G., and may¢ be contacted at the clubs BBS.)¢ (Phone: 616-657-2665).¢¢ NOTICE: This article originally¢ appeared in the February, 1989 issue¢ of Atari Interface Magazine and may be¢ freely distributed or reprinted in¢ non-profit User Group publications as¢ long as the article's author and Atari¢ Interface Magazine are credited AND¢ this notice is reprinted with the¢ article. All other publications must¢ obtain written permission from Unicorn¢ Publications, 3487 Braeburn Circle,¢ Ann Arbor, MI 48108, Phone: (313) 973-¢ 8825 before using this article. (Ed. I¢ understand that UNICORN is no longer¢ in existance. A.P.)¢¢ ----------------end-------------------¢