ADDING A SECOND (EXTERNAL) HARD DRIVE TO THE TANDY 1000HD The Tandy 1000HD comes with an internal 10 megabyte drive and the Western Digital WD1002S-WX2 controller board. This controller board is capable of handling two hard drives. If you have a 1000HD and wish to add a second hard drive to the system, it is possible, but you have to know how to do it. This document will detail the necessary steps. First, you must make a new set of cables for the hard drives. Each hard drive uses a controller cable and a data cable. The controller cable is a 34- lead ribbon with a 34-pin dip connector at one end. The data cable is a 20-lead ribbon cable with a 20-pin dip connector at one end. The cables in the 1000HD connect to the controller board with the dip connectors, and to the hard drive with card-edge connector. You have to determine first what kind of connectors you will need with the external drive. Some drives use DIP connectors, others use card edge connectors. The data cable for the external hard drive should be at least three feet long, to allow it to pass out of the 1000HD case to the external drive. The controller cable should be 8 to 9 inches longer than the data cable. You will need to fasten two connectors on the controller cable in addition to the first 34-pin DIP connector. The first one should be a 34-pin card edge connector and should be placed approximately nine inches from the dip connector which fastens to the controller board. Attach this connector so that it faces the OPPOSITE direction from the controller connector. Then, at the other end of the controller cable, attach the connector for the external hard drive. Be careful in making up these cables; a short in either cable could destroy the controller board! Figure 1 -- Controller Cable diagram (2) __ (1)||==========||=============================||(3) ~~ ~~ |----9 in.---|----------36 in.--------------| legend: (1) DIP connector to WX2 controller board (2) card edge connector to internal HD, facing in opposite direction from (1) (3) connector to external hard drive Remove the WX2 controller board from the 1000HD by removing the fastening screw at the rear wall and lifting the board straight up. Carefully remove both cables from the board and lay the board on a flat surface component side up, with the rear metal bracket to your right. Look carefully at the right side of the board, near the metal bracket. You will see a jumper block marked SW1, with 8 positions. Positions 2, 3, 4 and 5 (numbers AS MARKED on the board) should have jumpers. The positions are numbered 1 2 3 4 8 7 6 5. Positions 1 and 2 tell the controller board the capacity of the internal drive. Position 2 jumpered means a 10-megabyte drive with 306 cylinders and 4 heads which is the configuration of the internal hard drive. Positions 3 and 4 determine the size of the SECOND (external) hard drive. They are both jumpered. This defines a 30-megabyte drive with 512 cylinders and 8 heads. You must reconfigure for the type of external drive you are adding. The BIOS parameter tables can recognize four types, as follows: A: 512 cylinders, 8 heads, 30 megabytes (3,4) B: 306 cylinders, 4 heads, 10 megabytes (4) C: 306 cylinders, 6 heads, 15 megabytes (3) D: 612 cylinders, 2 heads, 10 megabytes (no jumper on 3 OR 4) The external hard drive you are connecting MUST be one of these four types. The numbers in parentheses indicate which positions of the SW1 jumper block must be jumpered to define it. Note that type D requires no jumpers. Configure the board as noted for the external hard drive you are connecting. The next step is to jumper the drive select position. This will be on the hard drive itself. Between the controller cable cable and the data cable connectors ON THE HARD DRIVE is a jumper block with 4 positions. Hold the hard drive so that the PC board attached to it is on the bottom. With the controller connector to your right, the jumper positions are numbered 1 through 4, left to right. The external hard drive must be jumpered as 3, or the second rightmost position. Attach the cables to the external hard drive. Make sure you attach them so that the cables go in the proper direction (usually in the direction of the pc board attached to the drive). Now pass the cables into the 1000HD. If you have only two boards the easiest way to do this is to move the memory board to the farthest slot, leaving the middle slot empty, and pass the cables through the opening in the back. If you have three boards attached, pass the cables above the boards. In this case do not place them on top of each other or they will be crushed when you close the case. Attach the other end of the controller cable to the WX2 board. Attach the data cable from the INTERNAL hard drive to the connector nearest the controller cable on the board, and the data cable for the external hard drive to the connector farthest from the controller cable. Carefully seat the controller board back into the 100HD expansion slot nearest the fan. Now attach the 34-pin card edge connector to the internal hard drive. Arrange the controller cable so that it is not putting any strain on the internal hard drive connector (you don't want this connector to pull loose without your knowing it, believe me!). Apply power to the external hard drive and computer If the drive select light on the external comes on immediately the cable is upside down at the external drive. Turn off all power and reverse the cable. Apply power again. Now allow the computer to boot. If you get a boot failure message, or if you are asked to place a system disk in drive A:, then the connector to the internal hard drive may be upside down. Check it. If the internal hard drive boots properly your next step is to check drive D:. Enter HSECT D: to hard-format drive D:. If you are successful, run FDISK. Select option 5 ("Select next hard drive") and define the partition size. REBOOT your system by pressing the red RESET button. This is very important and must be done after running FDISK. Now enter HFORMAT D: to format drive D:. If this format proceeds properly you are done.