Project X'tal: Twinkle crystal ball makes it lovely

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First of all, you need to prepare a crystal ball instead of a normal trackball. Then put LEDs underneath as a hard disk access lamp and a hard disk power indicator.

A hard disk access lamp blinks every time the processor has an access to hard disk, and a hard disk power indicator is turned on while power is on.

It is lovely to have different colors for access lamp and power indicator. No wonder you want to turn your Duo on more frequently!

Things you need

1. LED (Any LED is OK as long as it can fit under the trackball. Choose your favorite color!)

2. Wire (Thin wire is better, otherwise you will have a difficulty when you put it under the trackball. AWG#28 or #30 wire or wrapping wire should be fine.

3. A resistor (150 - 470 ohm depending on a LED you use) to control the electricity through a LED.

You have to calculate how much electricity to go through a LED. Too much electricity will destroy a LED. For example, if 10 mA of electricity will require;

(5V - 2V) / 10mA = 300 ohm

(where the voltage of HDD: 5V, and the voltage of LED: 2V)

Larger resistance will make a LED darker, and vice versa. Do not use a resistor less than 200 ohm.

4. A thin mount to fix a wired LED on. Any insulation material would do. Reflective material will be nicer.

5. Heat shrinkable tube for the insulation of soldered spots.

6. A crystal ball (You must find one with18.9 mm diameter. Try some crystal processing expert near you.)

7. A T8 torx driver

8. Solder and soldering iron

9. A tester

How to do it

1. Disassemble Duo and remove a trackball unit. (You must know how to do it!)

2. Before actually connect a LED, place a LED under a trackball to make sure that a LED does not touch a trackball. You should not put a LED just under the trackball but a little closer to the keyboard, otherwise you cannot see the light from a LED because it will come straight through the trackball.

3. Find which terminal of HD which is one of unused 'IN USE' terminals you should connect a LED to.

Here is how to find those terminals;

It is better to disconnect a film cable between a HD and a logic board.

<For a SCSI HD>

In the photo, the terminals (1) are 5V of HDD, and the terminals (2) are the ground (earth). The terminal (3) is 'in use'.

<For an IDE HD>

Unlike a SCSI HD, all terminals you need to find are within a cable connector film. When you see the terminals above a circuit board, the first terminals from the left are the ground, the second ones are 5V of HDD and the third ones are 'in use'.

4. A HD access lamp should be connected in order of 5V (HD) - resistor - LED - 'in use' terminal. Beware of the direction of LED. Cathode should be connected to 'in use' terminal. There must be an indicator on it.

5. A LED connected between 5V HD and the ground will turn on when the HDD is on. (It will turn off when HDD is not spinning.) This LED should be connected in order of 5V (HD) - resistor - LED - ground (earth) terminal.
Don't forget to insulate the wire connected to a resistor!

6. Reassemble Duo. Put the mount under the trackball unit and fix the connected LED with sticky tape on it. Be careful that the trackball unit does not interfere the wires.

AT YOUR OWN RISK!
Unauthorized modifications may not allow you to have a full support from Apple. And Duo-Zone International is not responsible for any damages caused by your attempts at those original projects described here. Make sure that you know exactly what you are doing!

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