720K External Drive  (250-1061)      Installation       Faxback Doc. # 5257

Adding Tandy's 720K External Disk Drive to your computer as a secondary disk 
drive significantly increases the amount of disk storage. This 3 1/2" floppy 
disk drive supports all standard MS-DOS version 2.11.24 and ROM BIOS commands 
and uses the 3.5", 80 track microfloppy diskettes.

* 720K bytes formatted storage, 1M byte unformatted

* Uses 3 1/2", double-sided, double-density diskettes

* Connects to a computer via a cable

* Front loading, horizontally-mounted

The external disk drive connects directly to your computer by the cable from 
the drive's rear panel.

CONNECTING THE DISK DRIVE

Caution should be exercised when using the disk drive in low humidity 
environments to prevent damage to electronic parts by static electricity 
being discharged through them. Before proceeding further, discharge any 
static electricity build-up by touching a grounded metal object.

1. Turn off power to all equipment. Disconnect the power cord form the 
   electrical outlet. If the computer is on, you could damage the central 
   processing unit, as well as your external disk drive.

2. Connect the external disk drive's cable to the EXTERNAL DRIVE connector 
   on the rear panel of the computer and to the disk drive.

INSERTING THE DISKETTE

Storing your files on diskettes gives you unlimited data file storage space. 
The disk drive uses a 3 1/2", soft-sectored, double-sided, double-density, 
80-track microfloppy diskette (26-417 or 26-418).

1. Follow the instructions in your computer operation manual for powering up 
   the system.

   Cover the write-protect notch (square hole in the upper right corner) on 
   the diskette when you want to change information on the diskette. 
   Otherwise, the disk drive can not write (change information) on the 
   diskette. Move the small tab (normally red or black) down to write-enable 
   the diskette or move it up to write-protect. The rule-of-thumb is that
   "If you can see through it, you can't write to it."

2. Insert the diskette with the label side up into the disk drive insertion 
   window.

   The LED indicator will light while the drive is in use. Push in the eject 
   button below the insertion window to remove the diskette.

   Before turning off power to the system, be sure to remove the diskette. 
   Leaving it in the drive may result in loss of the contents of the 
   diskette.

   For instructions on using data diskettes, making backups and formatting a 
   diskette, refer to the first part of "A Practical Guide to the Tandy 
   1000 EX."

ACCESSING INFORMATION

Information can be accessed from your secondary disk drive and copied to 
the 5-1/4" internal drive of the computer.

To access the secondary drive, give the drive reference in the command or 
pathname. For example, you might type:

       dir b:    or b:\program

A special function key is used to boot a diskette in the secondary drive 
which is designated as Drive B. Press [F3] during bootup after you hear the 
beep to swap drives and change the secondary drive's reference to Drive A.

For details on using software with your disk drive, refer to the first part of 
"A Practical Guide to the Tandy 1000 EX."

CARE AND MAINTENANCE

Your disk drive is designed to be free from periodic maintenance when it is 
operated within normal operation duty.

   * Five-year design component life
   * MTBF (mean-time-between-failure) equals 10,000 hours or more with power 
     on for typical usage

It is recommended that you clean the magnetic head with a cleaning disk to 
maintain reliability of the data.

If some of the parts in the disk drive are operated in a specially heavy-
duty condition, or if it is operated over 5 years, it is recommended that 
you have the unit serviced by a qualified Radio Shack technician.

Do not apply excessive impact or drop the disk drive on the desk.

(dtc-07/30/93)