Add a Hard Disk to a Kaypro "84" Floppy Computer The recent computer slump has resulted in massive parts dumping on the part of the computer manufactures to the surplus market. I am sure that you have seen all the ads in the papers hawking IBM ten megabyte drives for less than $500. Let me tell you how you can add a hard disk to your computer. All of the "84" series computers come with the larger power supply and the necessary power wiring for two drives and the hard disk controller. To convert to a K10 simply involves unplugging the lower drive, adding the controller and host interface boards, and plugging in some new cables. The following is a list of the needed parts: The hard disk itself Shugart 712 Seagate 224 The hard disk controller Western Digital 1002-HDO or 1002-05 Kaypro Host Interface 81-212A ( must be "A") System ROM Kaypro 81-302C Advent 84 Turborom Software Kaypro K10 F, G, or H System disk Advent Turborom software is supplied with its ROM Interconnect cables Dual 50 pin IDC ribbon cable (computer to host) Dual 40 pin IDC ribbon cable (host to controller) 34 pin IDC to 34 pin edge ribbon (controller to disk) 20 pin IDC to 20 pin edge ribbon (controller to disk) Hardware 8 4-40 1/2 in spacers 4 4-40 1/4 in flat head screws 12 4-40 1/4 1n binder head screws 8 #4 nylon or fiber washers The hard disk is available from many sources. In the December Byte Advanced Computer Products is selling the Shugart for $229 with a one year warranty. The Western Digital controller is also a standard part. Its list is $295. Xerox surplus outlet has them for $75 as is (the five I have purchased have all worked), S100 is supposed to have them new for $200, and ERAC has them used with warranty for $200. The host interface card is a Kaypro part. Your Kaypro dealer can order it for you for around $30 or you can get it from ERAC for $5. The cables are all standard parts. Most of the connectors cost 5 to 6 dollars each and 50 conductor ribbon cable is about a buck a foot. ERAC has the stock kaypro cables for around $3 each, but they are too short. You can reuse most of the connectors if you are careful and use them to help build up to ERAC's $25 minimum order. Their ad states that they have 81 series ROMs, so they might have the 81-302c in stock. Now for the construction. I despise overly detailed instructions, so I am only going to describe the work in general. If you need more specific hand holding, most user groups have at least one technical type that can help. Remove the main board, the floppies, and the floppy cage. Mount the host interface card on four spacers on the floor of the computer in the area normally covered by the cage. Mount it with the 50 pin connector facing the rear. Mount the controller card on the left side of cage. Be sure to mount it low enough to miss hitting the main board. I only used three spacers as the lower front one would be a real bitch to get a screw into. Countersink the holes and use the flathead screws so that they don't interfere with the drives. Temporarily set the cage back in place and make up the host cables. The forty pin connector goes to the forty pin connector on the controller. The fifty pin connector goes to the fifty pin connector on the main board next to the 34 pin floppy connector. Leave enough slack in the cables so that they can be adjusted to not block the air flow from the fan. Remove the controller and mount the cage. Mount the hard disk on the bottom and the floppy on the top. Both drives should have terminators and be strapped for the lowest drive number, on some drives that is 0 and on some it is 1. Mount the controller card using the insulators so that none of the foil tracks on the top or bottom are shorted. Make up the drive cables. The 34 pin cable goes to the 34 pin connector on the controller next to the power plug. The 20 pin cable goes to the center of the three clustered 20 pin connectors J2. Remount the main board and plug in all of its cables. Plug in all the power cables. The controller gets the one with only a white and black wire. Plug the floppy cable back in using either of the edge connectors. Change the ROM. If you are using the Kaypro ROM it will be shorter and goes all the way to the rear of the socket. The rest of this assumes that you are using the stock Kaypro ROM and software. For the Advent Turborom refer to its instructions. To use the Turborom, you must purchase their Hard Disk Formatter also. Power up the computer with the system disk in the floppy. It should come up with Kaypro 10 1.9E message and then boot from the floppy normally. After at least warming up for half an hour we can now format the hard disk. Run Format and tell it that your drive is 1,1 head 0,3 cylinders 0,305. It takes about 45 minutes. Now run Findbad B: and Findbad C: to lock out any bad blocks. Run Putsys and Putovl to write the system to the hard disk and you are done. Open the floppy door, push reset and it should boot from the hard disk. One of the nice things about Kaypro is the extensive public domain support. John Smith has supplied a turnkey ZCPR3 system that will run on your new machine by simply running a new set of put files. Most kaypro user groups have it and it is on the major boards. I recommend it highly. It would be a hardship to go back to the stock CP/M system. It makes a hard disk even nicer. I have modified several machines with no problems. Since the entire job involves only board swapping, with a little care you should have none either. Glenn Drayer 15200 Magnolia #19 Westminster, Ca 92683 ...ONKUG, Newsdiskette to Kaypro Users Groups, Volume 2, Number 2.