How to Convert a 2600 Driving Controller into a

                       Rotary Controller for Tempest 2000

                                       by

                                 Kenneth Sumrall

                                 ken@cup.hp.com



                       ==================================



First of all, I'd like to thank the following people for posting info on

rotary controllers they've built, since they helped me make my own rotary

controller: 



     Uwe Roeger (uwer@aragon.bb.bawue.de), for posting a schematic of the

       jaguar controller.

     Andrew Hague (andrew@minster.york.ac.uk), for posting schematics for

       using an Atari ST mouse for a rotary controller.

     Andy Light (alight55@aol.com), for his instructions on making his own

       rotary controller.

     Ben Johnson (benjohnson@aol.com) for his suggestion to use a

       momentary toggle switch mounted in a 2600 Driving controller, and

       also for the suggestion to mount a DB-9 jack in the Jaguar

       controller to interface to the rotary controller.  He also

       suggested adding lead weight to the controller to make it spin

       better.



These instructions are broken down into three parts, part 1 describes the

modifications to the Jaguar controller, part 2 describes the modifications

to the 2600 Driving controller, and part 3 describes how I added lead

weight to the rotary controller to improve its spin.  The driving

controller will still work on the 2600 Indy game after performing these

modifications. 



The following connection table is used in the first two parts of the

instructions.  It briefly describes the connection of the the DB-9 jack to

the Jaguar controller, and the wiring of the additional switch on the 2600

Driving Controller. 



+-----+---------------+---------------+---------------+-----------------+

|     | Rotary        | Sega cable    | Jaguar        | Jaguar          |

|DB-9 | connection    | color         | function      | connection      |

+-----+---------------+---------------+---------------+-----------------+

+-----+---------------+---------------+---------------+-----------------+

| 1   | right side    | Brown         | Right         | Ribbon cable 2  |

|       encoder       |               |               |                 |

+-----+---------------+---------------+---------------+-----------------+

| 2   | left side     | Red           | Left          | Ribbon cable 12 |

|     | encoder       |               |               |                 |

+-----+---------------+---------------+---------------+-----------------+

| 3   | B switch      | Orange        | B             | DB9 connection  |

|     |               |               |               | to 4148 Anode,  |

|     |               |               |               | Cathode to Jag  |

|     |               |               |               | controller pin 3|

+-----+---------------+---------------+---------------+-----------------+

| 4   | C switch      | Yellow        | C             | DB9 connection  |

|     |               |               |               | to 4148 Anode,  |

|     |               |               |               | Cathode to Jag  |

|     |               |               |               | controller pin 2|

+-----+---------------+---------------+---------------+-----------------+

| 5   | B/C common    | Green         | Keypad B      | IC pin 4        |

|     |               |               | and C row     |                 |

+-----+---------------+---------------+---------------+-----------------+

| 6   | Button A      | Blue          | A             | Ribbon cable 5  |

+-----+---------------+---------------+---------------+-----------------+

| 7   | N/A           | Grey          | +5V           | IC pin 20       |

+-----+---------------+---------------+---------------+-----------------+

| 8   | Encoder       | Black         | Left/Right    | Ribbon cable 1  |

|     | center and    |               | column enable |                 |

|     | button A      |               |               |                 |

+-----+---------------+---------------+---------------+-----------------+

| 9   | N/A           | White         | Ground        | IC pin 10       |

+-----+---------------+---------------+---------------+-----------------+



One last thing before you start, these modifications worked for me.  If

they don't work for you, you're on your own.  I can't accept liability for

any damage you do to your system/controller/yourself. 





Part 1: Adding a DB-9 connector to your Jaguar Controller.



 Parts needed:

  1) DB-9 male connector

  2) Lots of 30 AWG wire wrap wire

  3) Two 1N4148 diodes

  4) Two 4-40 screws, with lock washers and nuts



 Tools needed:

  1) An exacto knife to remove the rubber caps over the screws.

  2) A number 1 Phillips screwdriver.

  3) A low wattage soldering iron with a small tip.

  4) Some contact cement.

  5) A tool to cut a mounting hole in the Jag controller case.

     I used a Dremel tool to cut the hole, and a drill press to

     drill the mounting screw holes.



  A good supply of patience is also recommended.



1.  Carefully remove the 4 rubber caps on the back of the Jaguar

    controller.



2.  Remove the 4 screws holding the controller together.



3.  Remove the 2 screws holding the circuit board to the case.



4.  Remove the circuit board.



5.  Cut a hole in the center bottom part of the back shell of the

    controller.

    This is where you will put the DB-9 connector.  This is probably the

    hardest part of the project.  Once the hole is cut, put the DB-9

    connector in place, and check for proper fit by putting the two empty

    pieces of the shell together.  If things don't fit, file them down

    until they do.  I actually had to file down a small piece of the DB-9

    connector I used.  Be careful, but be creative.



9.  Drill the two mounting holes for the DB-9.  Make sure everything fits.



10. Using the wire wrap wire, solder nine connections using the left most

    and right most columns in the table above.  The DB-9 pin numbers are

    usually marked on the connector itself.  Look closely.  You may need

    to use a magnifying glass.



    The pin numbers for the ribbon cable refer to the cable that connects

    the joypad circuit board to the main circuit board.  I numbered them

    from 1 to 13, with the number one wire near the outside of the board.



    The IC's pins are numbered in the standard way.



    The connections DB-9 pins 3 and 4 may need a little extra explanation.

    You should hook up the Anode of the diode to the DB-9 connector, and

    the Cathode to the controller circuit board.  I don't know if these

    diodes are strictly necessary or just a protection measure, but I'm

    just copying parts of the circuit diagram of the original Jaguar

    controller.  The connection to the jaguar port pins 2 and 3 was made

    where the cable attaches to the board near the the IC.



    The power pins are not needed to use the 2600 driving controller, but

    if you ever want to add a controller that needs power, you won't need

    to rewire your Jaguar controller.



11. Once everything is connected, mount the DB-9 connector to the rear

    shell, and screws the controller board in place.  Now test all the

    connections you wired, and check for shorts between pins that you

    soldered.  If everything checks out OK, carefully put the two halves

    of the shell together, making sure you don't pinch any wires, and

    screw the case together. 



12. Using contact cement, carefully glue the rubber pads back in place.





Part 2: Modifying the 2600 Driving Controller for use with Tempest 2000



 Parts needed:

  1) Genesis joypad extension cable (about $10 at Electronics Boutique).

  2) Small SPDT Momentary-Off-Momentary switch.  I ordered my switch

     from Digi-key, part number CKN1088-ND, for $6.78.  It is by no means

     the only switch that will work, but it was small, and easily

     obtainable.  Digi-Key's phone number is (800) DIGI-KEY.  I am in no

     way affiliated with Digi-Key.  BTW, if you order less than $25 of

     stuff from Digi-Key, they will tack on a $5 processing fee for the

     purchase. 



 Tools needed:

  1) Drill

  2) Wire cutters and strippers.

  3) Exacto knife.

  4) Small wrench to tighten switch mounting nut.

  5) Soldering iron.

  6) #2 Philips screwdriver



1.  Remove the 2 screws holding the 2600 controller together.



2.  Unplug the switch from the wires attached to it.



3.  Unsolder the three wires attached to the shaft encoder.



4.  Throw away the old cable.



5.  Cut off male connector (Ouch!) from the Genesis extension cable.



6.  Using the exacto knife, cut back 2 inches of the outer insulation

    exposing the 9 wires.



7.  Strip about 1/4" off the end of each individual wire.



8.  Drill a hole in the top half of the driving controller to mount the

    switch.  I mounted mine almost exactly opposite of the original

    button.  Experiment with what would feel right for you.



9.  Mount the switch in the hole, and tighten the nut.



10. Solder the wires from the extension cable to the controller.  Use the 

    3 left most columns of the chart above as your guide.  Make sure that

    your cable colors match the DB-9 pin numbers the same way that mine

    do.  If they don't, adjust accordingly.



11. The power and ground wires aren't used, so cut them off.



12. Check all your connections, and make sure you don't have any shorts.



13. Carefully put the case back together.





Part 3: Adding lead weight to your 2600 Driving controller



This part is not necessary, but it does improve the spinning action of the

2600 Driving controller, which helps, since the 2600 driving controller

only produces 16 pulses per revolution. 



I weighed the finished weight on my kitchen scale, and it came in at 4

ounces.  I think there is room in the controller for more lead, and

therefore, more weight, but I don't feel like building a new weight.  If

you decide to experiment, I would recommend AGAINST increasing the

diameter beyond 1.5 inches, since 1.5 inches almost rubs agains the

pushbutton in the controller housing.  I would use more big circles, and

fewer little circles (see below).  You could probably fit 5 and maybe 6

ounces in there, but that is just a guess. 



 Parts needed:

  1)  Lead sheet, .036" or so in thickness.  I bought mine at the Orchard

      Supply hardware store down the street from my house.  I bought 8

      ounces of this, measuring 12 inches by 2.5 inches.  WARNING!  LEAD

      IS TOXIC.  ALWAYS WASH YOUR HANDS AFTER WORKING WITH IT,

      ESPECIALLY BEFORE EATING!

  2)  Some type of glue.  I used Barge contact cement, which I also bought

      at Orchard Supply hardware.  Epoxy would probably work also, but

      I've never tried to glue metal with epoxy.

  3)  #2 wood screw, 5/8 inches long.

  4)  Flat washer for #2 screw.  I couldn't find a #2 washer at Orchard

      Supply, so I bought an M3 metric washer instead.



  Tools needed:

  1)  Sheet metal shears.  Ordinary scissors could probably be used, since

      lead is pretty soft, but I haven't tried it, and it may damage your

      scissors.

  2)  1/4" drill, 3/32" drill and 1/16" drill.

  3)  A vise is helpful.



1.  Scribe seven circles 1.5 inches in diameter on the lead sheet.  You

    can use a compass, or trace around a round object.  I traced around a

    bottle of epoxy resin I had near my workbench.  I used a diamond tip

    scribe, but almost anything can make a mark on lead.  If you don't

    have a scribe, try using an old mechanical pencil with no lead in it.



2.  Scribe 3 circles 7/16 inch in diameter.  I traced around my 7/16 inch

    drill for this one.



3.  Carefully, cut out all the circles.  The cutting action will bend the

    edges of the circles, so I re-flattened them with my vise when I was

    done. 



4.  Scribe 1 circle 3/8 inch in diameter.  Drill a hole 1/4 inch in the

    middle of this circle.  Cut it out with the shears.  Flatten it in a

    vise.



5.  Glue the 7 large circles together.  If you use the Barge contact

    cement I used, apply cement to one side of a circle, and press another

    circle to it.  Then, immediately separate the two circles, and let the

    glue dry for about 12 minutes.  After 12 minutes, press the two glued

    faces together.  This stuff sticks REALLY good to itself, so line it

    up carefully before putting it together.  Repeat until all the circles

    have been been glued together.



6.  Glue the 3 small circles together as described in step 5.



7.  Carefully mark the center of the top large circle, and the center of

    the top small circle.  If you used a compass, the center mark should

    still be visible.  Drill a 3/32 inch hole through both stacks of lead

    circles.



8.  Glue the small circle stack to the large circle stack.  Use the screw

    through the holes you drilled to properly line up the two stacks.



9.  Glue the 3/8 inch diameter ring to the bottom of the small stack.

    Center it carefully.



10. Make sure the completed lead weight fits over the plastic shaft that

    turns the shaft encoder in the 2600 Driving Controller.  The 3/8 inch

    ring should provide enough clearance over the end of the shaft for the

    weight to rest nicely on the shaft encoder.  It should also not short

    out any of the connections on the encoder.



10. Drill a 1/16 inch hole in the plastic shaft that turns the shaft

    encoder in the 2600 Driving Controller.  Drill this hole about 1/4 to

    3/8 inch deep.



11. Glue the lead weight to the shaft encoder.  Use the screw with washer

    through the 3/32" hole to align the weight as you glue it to the

    encoder.  Then screw the screw down.  Don't forget to use the washer,

    and don't screw it in too tight.  I noticed that when it was screwed

    in too tight, the shaft didn't turn as freely as when I loosened it a

    bit.





End of article -- reformatted by Carl Forhan (forhan@millcomm.com)