AOL File Library: 2,801 to 2,900/aol-file-protocol-4400-2801-to-2900.zip/AOLDLs/TAWUG/TAWUG Disk No. 25 (SHK)/TAWUG.25.shk/FLOPPER.PRO

AppleWorks Document | 1986-02-23 | 16KB | 258 lines

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DICK'S FLOPPY FLIPPER
R. W. Reynolds
F     Much has been said about the use of the back side of a disk. The H
Fgeneral and probably the safest is DON'T. The easiest way is to notch G
Ethe other edge. When the rear is used, the disk rotates backwards in F
Dthe case. There is a cleaner material in the case that continuously G
Ewipes the dust and dirt from the surfaces and retains it. Running in F
Dthe reverse may dislodge some of this and re-dirty the surface. The E
Cnew notch can be made with any of the many commercial devices that D
Bautomatically position the notch or by locating the position from H
Fanother disk and punch out a semicircle with an ordinary quarter inch E
Cpaper punch. These sometimes backfire because the case material is F
Dapparently a little brittle and small pieces may fracture and enter E
Cthe case. These may travel with the disk and damage the read write F
Dhead. A little safer method is to use a good sharp pair of diagonal H
Fside cutters (dikes). Mark location from another disk. Don't try with F
Da set of heavy electrician's type. These are not delicate enough to F
Dcontrol the location. Use a pair designed for small electronic work F
Dpreferably the flush cut type. A pair of scissors can also be used. H
FCare must be taken to keep the cuts shallow so the disk itself is not
damaged.D
B     The write protect switch is a normally closed device. When a H
Fwrite protected disk is inserted, the switch is opened and no writing F
Dcan be done on the disk. Therefore a simple toggle switch placed in C
Aparallel will make the circuit think the write protect switch is @
>closed when a protected disk is in the drive. Now we are in a 9
position to control the function and write on the back.F
D     A few more steps can be taken to make life easier. If a double D
Bpole double throw center off switch is used, another condition is H
Favailable. That is write protecting a notched disk. The other pole of F
Dthe switch is used to control a red/green LED. This gives a visible F
Dindication of the position of the switch. I made it:- (switch down, F
Dnormal operation, LED green; switch up, write protect override, LED 2
red; switch center, all write protect, LED off).E
C     The parts are available from any electronic supply store. The C
Aswitch is a miniature DPDT center off (about $2.50) and measures F
Dabout 1/2" square (pick the kind for panel mounting. The LED can be D
Beither a two wire type or a common cathode three wire type (about @
>$1.50).You will also need a 3K (3000) ohm 1/4 watt or 1K 1/4W G
Eresistor, depending on LED, (a few cents).The two wire LED takes the D
B3K. You can do a much neater job of wiring if you get a length of 6
ribbon cable; six wires by about twelve inches long.D
     The following description applies to an APPLE disk ][ single E
Cdrive. The idea and circuitry can probably be modified to apply to F
Dalmost any drive. These instructions will work for an APPLE ][, ][+ F
Dor ][e with either one or more single drives.The APPLE DUO drive is F
Ddifficult to open and is pretty cramped inside. You are on your own D
Bthere. Turn off the power switch on the computer. Leave the power H
Fcord in place (this keeps the system grounded). Open the computer and H
Ftouch the power supply case to remove any static charge your body may D
Bhave accumulated. Do this often during modification and any other F
time you go inside the box. It can't hurt and it may help. Move the
<drive (preferably drive 2) to a work space. You may want to F
Ddisconnect the drive for convenience but leaving it connected keeps H
Fit grounded. Open the drive by removing the four screws on the bottom H
Fthen slide the cover to the rear to remove it. All hand refrences are B
@yours when facing the front of the drive.You may want to play a F
Dlittle here. You can turn your machine on and work the drive to see E
Chow it does it's thing. Put a disk in the drive and watch it boot. E
CThere is a red LED on the upper left corner of the mother board on F
Dthe ][e that signals "POWER ON" just as a reminder. Remove the disk H
Fslowly. You can feel and hear the disk depress the button and release 3
it when all the way out.
Turn the machine
5     Remember NEVER
repeat
 NEVER plug in or remove
6     cable, card, chip or device when the computer is
D     Locate the two wires from the write protect switch. They go to G
Ethe plug in the center back of the top board; they are usually brown F
Dand black and enter the plug near your right. Cut either wire about D
Ban inch or less from the plug and strip about 1/8" from each end. H
FBare about 1/4" of the other wire in the same area. Do
 cut this G
Ethis wire. You may have to slide a cable tie along the bundle to get C
Aabout two inches of wire between the tie and the plug. Cut three F
Dwires about twelve inches long and strip the ends about 1/4 inch or A
?use the ribbon cable. Solder a wire to each cut end and to the E
Cstripped side of the other. Insulate the bare joints. Use sleeving A
?and/or tape. It will be easier if you remove this plug. Layout G
Elocations for two holes. The left location is for the switch and the D
Bright is for the LED. NOW make sure the switch you have purchased D
Bfits between the two ribs in the rear of the front plate and will D
Bmount in the hole without interfering with a rib. You may want to F
Dremove the front plate. This requires popping off the retainer ring E
Caround the drive LED and releasing the it from it's clips. This is C
Asometimes difficult. WATCH the door mechanism. Remember you must #
reassemble and adjust this later.H
F     Measure for the hole sizes your devices need and drill the holes H
FWatch that the drill does not walk and be very careful breaking thru. F
DDON'T let the drill jab thru and do damage. It may be smart to turn C
Athe drive over so the chips do not fall into the mechanism or to G
Eplace a baffle behind the front plate if you use a drill press. Just H
Fuse your head. Remove front nut and plate from the switch. Adjust the G
Erear nut for proper stick thru for plate and front nut. You may have D
Bto remove a locating tab from the front plate. Or if you want to, H
Fdrill a locating hole for this tab as deep as necessary. WATCH; there H
Fis usually an orienting key in the plate hole. Remove the top circuit H
Fboard and let it hang . Just remove the two screws and slip the board C
Afrom under the two clips and lay it aside hanging by it's wires. @
>Remove the small plug on the right side of the board for more (
freedom. It will go back only one way.E
C     Mount the switch. Solder wires to the left side of the switch F
D(see circuit diagram). You may want to do this work with the switch E
Cunmounted. Kind of close quarters here anyway. Position switch and F
DLED in their holes in the front plate. (For a two wire LED) arrange H
Fto solder the 3K resistor between the right center switch lug and one H
wire of the LED. This connection holds the LED in place so arrange it
Cdirect and stiff. Make these connections and solder them. Use heat F
Dspareingly on the LED it is heat sensitive. If you have a heat sink E
Cclip, use it here. Prepare three wires about twelve inches long or E
Cthe ribbon cable. Tin the free ends of these wires. Now reassemble F
Dthe front panel and the top circuit board to the drive if they have G
Ebeen removed and replace the drive LED. Make sure the wires from the G
Erear plug to the new switch are on the top of the board. Replace the F
Dread/write head plug on the right side of the board. Take care that ;
the door mechanism assembles properly and works smoothly.E
C     The power for the LED is taken from the terminal strip in the G
Eleft rear of the top board. Pins 1, 3, 5 & 7 (left - top) are ground E
Cand common, pin 9 (fifth from left - top) is negative 12 volts and D
Bpins 13, 15, 17 & 19 (right - top) are positive 12 volts. Tin the E
Ctops of pins 1, 9 & 19 between where they go down to the board and B
@the rear of the terminal strip. You may want to remove the plug H
Fretainer clip for this. Lift it straight up. Solder the wire from the G
ELED to pin 1. Do not add solder- just melt what is there. Dress this G
Ewire and the other two, when soldered, to the rear of the drive. You F
Dmay want to figgure out the LED polarities and solder the other two H
Fhere, otherwise go on. The front end of the wires should be even with G
Ethe down-bend of the connector otherwise the terminal retaining clip H
Fcannot be removed or installed later. Plug drive cable onto the drive F
Dcard if it was removed. The red stripe on the ribbon cable is pin 1
and goes on the left.F
D     Now for a test:- Make sure that all cable connections are made H
Fand firm and that the system is in runable condition except of course G
Efor covers. Make sure the two loose wires from the switch are out of G
Econtact with any circuitry. Recheck to see that the three wires from G
Ewrite protect switch circuit go to left three lugs of the switch and H
Fthat the switch handle works vertically. Make sure that the power for E
Cthe LED (right side of the switch) is completely isolated from the D
Bdrive circuits. Turn the computer on. Drive 1 should start. Put a D
Bdisk, say a Master, in drive 1 and close the door. Wait for boot. H
FMove switch to bottom position. Take the wire from the switch top lug G
Eand touch it to pin 19 (right side). This is safe because these last H
Ffour are the same. The LED should glow green and you are on the right C
Atrack. If it is red, (oh well - 50/50) throw the switch clear up H
F(remember center is off), take the wire from the bottom lug and touch H
Fpin 19. The LED should glow red. Now we know which is which. TURN THE F
DCOMPUTER
. Solder the proper wire to pin 19. Remember dress to A
?the rear. Solder the other wire to pin 9. Now you can test the C
Asystem. Set up to copy (any copy program will do). Follow normal F
Dprocedure with the switch down (green light). This copies only to a F
Dnotched disk. Re-try with the switch in the center (light off). You H
Fshould get a `DISK WRITE PROTECTED' or some such error. Turn the disk C
Aover (un-notched), throw the switch up (red light) and copy. Now D
Byou're in business. Have fun BE CAREFUL.
Have the switch up (RED C
ALED)
 when you want to write to a protected disk.
 You can G
Ewreck a valuable program. Keep your head screwed on straight. If you H
Fwant to you can redesign this and have the switch mounted on the back C
Apanel of the drive. This may be wise if you have infant computer
wizards.D
B     The two wire LED requires both polarities + & -. The 12 volt G
Enegative supply is very weak thus the 3K resistor limits the current H
to about 3 milliamps. The three wire LED is a common cathode unit and
Cis to be wired into the 12 volt positive  power supply. It will be E
Cbrighter. This device is to be wired using similar techniques. The H
Fcathode, usually the center wire, is connected to the common (pin 1). @
>of the input plug. Insulate the bare lead and the others when E
Cconnected with sleeving or tape. The switch center lug connects to G
Ethe positive (pin 19) thru a 1K resistor. This allows about 10 MA to G
Eflow. The two leads to the LED anodes connect to the upper and lower F
Dlugs of the switch right side. Either reason the connections out or ,
do a similar experiment described earlier.F
D     While the drive is open for this work a couple more things can H
Fbe done. Layout and drill a three eighths hole in the right rear side H
Fof the drive cover so that the speed adjust trim potentiometer can be E
Creached without removing the cover. A one inch hole can be made in D
Bthe bottom plate so that you can see the strobe disk on the drive E
Cpulley. These changes will allow you to check and adjust the drive E
Cspeed using a florescent light without taking the drive apart. The D
Bhole can be covered with a piece of plexiglass taped in place. At H
Fleast, tape a piece of cardboard over it. Keep the other hole covered F
Dwith a piece of masking tape. It almost matches the drive color. If G
Eyour drive needs cleaning and you know how, this is a good time. Tie F
Dthe wires into a cable with ties, string or thread and arrange them C
Aout of the way to the left side if you used hookup wire. The 12" E
Cwires will allow good clearance when the board is removed for head D
Bcleaning. Reassemble the drive covers (be careful that no wire is !
pinched) and close the machine.F
D     I normally leave the switch centered. When I try to write to a F
Dprotected disk the machine will call me a dummy and I reach out and E
Cflip the right switch in the proper direction and continue on as a G
Esafe dummy. I have modified both of my drives and find life a little G
Eeasier. The main utility of this system is the storage of data, text E
Cand little used programs and when you run out of blanks. Ones that C
Aare used often should be stored normally on the front side. This F
Dkeeps the reverse rotation to a minimum. A second use is to store a G
Ebackup copy on the back where it is convenient and handy. This whole D
Bthing is becoming less economic as the price of disks falls. It's
still handy to have around.
REYNOLDS ENGINEERING;  17306 BRYANT LANE; HAZELCREST IL 60429;
312/335-2574
APPLE TREE COMPUTER CLUB; 1544 EDGWOOD; CHICAGO HEIGHTS IL
THESE ARE WORTH 1000 WORDS
                  CIRCUIT MODIFICATION SCHEMATIC
             |-------------------|----------------;
    WRITE    |                   |                    TO=
  PROTECT    X  TOP LUG> |-X-|-X-| <BOTTOM LUG      CENTER<
   SWITCH    |-----------|   |--------------------   PLUG!
                             ^!
                             |$
                 DPDT --LEFT POLE%
                SWITCH--RIGHT POLE<
                                                         D
                             \/                      (TO) (VOLTS)E
                   |------------------------------   PIN 1  0   OFF
  TWO WIRE         |     |------------------------  (PIN 9  - INPUTE
  RED/GREEN  |-|>--|     |       |----------------  (PIN 19 + PLUGF
     LED --> |-<|--|     |-X-|-X-|                  (CHECK POLARITY>
             |               |                      (OF LED2
  RESISTOR-> |--XXXX---------|  3K OHM 1/4 WATT
                    ALTERNATE (THREE WIRE LED)
                 DPDT%
                SWITCH--RIGHT POLE!
  THREE WIRE                \/6
  RED-GREEN  |-|>----------------|<-(CHECK POLARITY.
     LED --> |-|>--------|       |  (OF LEDA
             |---------| |-X-|-X-|                       VOLTSD
                       |     |                       TO        OFH
  RESISTOR  1K OHM --> |     |--XXXX--------------  PIN 19 + INPUT   D
           1/4 WATT    |--------------------------  PIN 1  0 PLUG
              UPPER LEFT CORNER OF DRIVE
  HOLE CENTER FOR  SWITCH LED7

       \/   \/
             |                      ____________ /4
         --->|  3/4" |1/2"|<---    |            /6

  |_.___._|_.__|_.__    |            \C

5/16"
  |  1/4-/|    |\13/16* |   DOOR      \  *25/64 FORD
       _____ |_____________________|             /     3 WIRE LED5
        /\   |  ___________________|_____________\8
             | |
   DRIVE SLOT
|              \7
             |_____________________|_______________\7
             |                     |               /6
             |  /\/\/\    /\/\     |/\  /\        /5
              \/      \/\/    \  /\/  \/  \    /\/2
                               \/          \/\/
                      ^^ DIAGRAMS & SKETCH ^^