Sprinter K Speed Up Board
Installation/Programming Instructions
KAYPRO SPRINTER INSTALLATION INSTRUCTIONS PRELIMINARY OUTLINE
The SPRINTER K by Holmes Engineering is a completely assembled plug-in "speed-up board" for the Kaypro II computer. The SPRINTER will reliably double the operating speed of your Kaypro. The SPRINTER slows down to normal operating speed during disk read and write operations, and during I/O operations.
No modifications to the Kaypro II are required. Installation is simple and requires only the ability to remove parts from sockets on the Kaypro II circuit board, and plug parts of the SPRINTER into the emptied sockets. No soldering is required.
INSTALLATION INSTRUCTIONS
IMPORTANT
BEFORE INSTALLING THE SPRINTER IN YOUR KAYPRO COMPUTER, UNPLUG THE POWER CORD FROM THE WALL OUTLET!!!! NEVER WORK ON YOUR KAYPRO WITH THE POWER CORD PLUGGED INTO THE WALL OUTLET; LETHAL VOLTAGES ARE PRESENT INSIDE THE KAYPRO WHEN POWER IS APPLIED!!!!!!!!!!!
1. Remove the four screws on each side of the KAYPRO top cover, then remove the two screws on top of the KAYPRO top cover. Lift the top cover off and set it aside.
2. Once the top cover is removed, the main circuit board is clearly visible when looking down at the top of the computer. Notice that each part is labeled. Locate the Z-80 microprocessor "chip" labeled U63, toward the front center of the main circuit board.
3. Insert a small flat-blade screwdriver (or similar object) under U63 and pry one end out of the socket. Then insert the screwdriver under the other end of U63 and pry it out of the socket. If necessary, go back and forth between the two ends until U63 can be removed from its socket. Remove the protective foam from the SPRINTER pins and press it onto the Z-80 pins, then set the Z-80 aside.
4. Locate a 74LS293 labeled U86 toward the front edge of the main circuit board. Use the small screwdriver to remove U86 from its socket just as you did U63. Press the pins of U86 into the foam you placed on the Z-80 you removed earlier.
5. Pick up the SPRINTER and examine the two rows of pins on the back of the board. If any of the pins are bent, GENTLY bend them back into position.
NOTE: THE NEXT FEW STEPS ASSUME YOU ARE LOOKING AT THE KAYPRO FROM THE FRONT.
6. Orient the SPRINTER so the part numbers printed on the integrated circuits are RIGHT SIDE UP.
7. Place the SPRINTER pins into the openings in the socket at U63, but do not press the pins into the openings in the socket yet. Look under the SPRINTER board and make sure that the pins are properly inserted into the socket. An improperly positioned pin could break off when you press the SPRINTER into place!
8. Double check the orientation of the SPRINTER; the small notch at the end of the Z-80B should be facing to the left of the computer, when viewed from the front of the computer. PLUGGING THE SPRINTER IN BACKWARD COULD CAUSE DAMAGE TO THE SPRINTER OR YOUR KAYPRO! TAKE THE TIME TO DOUBLE CHECK NOW!!
9. Place one hand under the KAYPRO circuit board, and press the SPRINTER pins firmly into the socket at U63. It is sometimes difficult to tell if the pins are all the way into the socket. You should be able to tug gently on the SPRINTER without pulling it from the socket, and the SPRINTER should be parallel to the KAYPRO circuit board.
10. There is a 74LS293 integrated circuit attached to the SPRINTER via a red wire. Plug this I.C. into the socket at U86. Once again, make sure the notch at one end of the I.C. faces to the left when viewed from the front of the comuputer.
11. Remove one nut from the toggle switch attached to the SPRINTER via a three-wire cable. Insert this switch into a ventilation slot in the rear panel of the case, so the toggle arm of the switch extends out where you can actuate it when the case top is replaced. Place the nut on the switch and tighten it finger tight. Orient the switch so it travels either horizontally or vertically (whichever you prefer). Do not tighten the nut any further at this point.
12. Place the top cover back on your KAYPRO, but do not replace any of the screws yet. You are now going to test your system and verify that everything is working correctly.
13. Place a CP/M system disk in Drive A and a blank disk in Drive B. Format the disk in Drive B as instructed in your KAYPRO manual. When the FORMAT (NOTE A) program begins verifying tracks on the disk in Drive B, switch the SPRINTER switch (on the back panel of the KAYPRO) through all of its positions. You will notice that one of the switch positions will cause the verify process to proceed much faster; this is the high-speed position for your SPRINTER. Leave the switch in this position, then rotate the switch so it "points" upward in the high-speed position and tighten the mounting nut to hold the switch firmly in place. (Of course, you may orient the switch any way you choose, though it seems "natural" to have the up position of the switch represent high speed, and the down position represent low speed.)
NOTE A: CURRENT KAYPRO SYSTEMS DO NOT INCLUDE THE VERIFY SECTION OF THE FORMAT PROGRAM. AN ALTERNATIVE TO DEMONSTRATE THE SPEED UP IS TO WRITE THE FOLLOWING PROGRAM IN MBASIC.
10 PRINT "DEMO SPRINTER -K SPEED UP BOARD"
20 FOR I = 1 to 5000
30 Z = Z + 1
40 NEXT I
50 GO TO 10
RUN
Any program which scrolls on the screen will demonstrate difference between high and low speed. A good example is the game HORSE.BAS. When running the game switch between high low speed. An increase in speed of approximately 20 seconds will be noticed.
Problems with the SPRINTER are rare due to the good design of the KAYPRO computer. If a problem is going to occur, the FORMAT program will not run, or it will begin showing format errors at high speed which it does not show at normal speed. If this should occur, you should try erasing the disk you are formatting in Drive B. The FORMAT program doesn't work as well with disks that have been previously formatted. The disk may be erased with a bulk disk eraser, or with a permanent magnet eraser (such as the DISK WAND, available from your dealer or from Holmes Engineering). Once you have erased the disk, the format program should run as normal (only much faster!).
OPERATING THE SPRINTER
Operation of the SPRINTER is simplicity itself! When you wish to run at normal speed, set the speed switch so it in its down position. When you wish to run at high speed, place the switch in its up position. When running at high speed, the SPRINTER will automatically slow to normal speed when you read or write a disk, or when you access an I/O port. The SPRINTER will also add a little delay to memory access cycles to ensure that the memory in your system has time to respond to the faster system speed. This delay is added only in the high speed mode.
You may have noticed that the speed switch on your SPRINTER also has a center position, where it is neither in the high speed or the low speed mode. This center position allows software control of system operating speed! Thus, if you wished to switch speeds under program control, you could set the speed switch to its center position and write software commands into your program(s) which could control the systems operating speed!
The SPRINTER is addressed at port 5FH (95 decimal). In a BASIC program, the commands for switching speeds would be:
OUT 95,0 (switches to normal speed)
OUT 95,1 (switches to high speed)
The commands in Z-80 assembly language would be:
Low speed:
LD A,00 ;load A register with 00
OUT 5F,A ;send the contents of A to port 5FH
High speed:
LD A,01 ;load A register with 01
OUT 5F,A ;send the contents of A to port 5FH