Purple G4 w/ HD Activity LED
Written by Dr. Bob   
Friday, 13 August 2004



As featured in Acara Magazine!
  This mod changes the G4 color as well as adding a HD activity led.



 

 

 

Note the Blue LED I installed behind the Apple logo. It blinks whenever the disk array is accessing.

 

 

Now if I could only paint on a SCSI port...

 

 

The marbling effect is cased by inconsistant translucency of the clear panels.

 

 

By painting the inside of the plastics, I was able to preserve the shine of the front panel.

 

 





Specifications:


 

  • 512MB of PC100 RAM, 140GB disk, True 52X Kenwood CD-ROM
  • 16MB Rage 128Pro AGP Graphics Card, Airport
  • Adaptec 3950U2W SCSI Card, Adaptec 2940UW SCSI Card

 

 

How I installed the LED:


Basically I used a standard T1-3/4 sized Blue LED. You can buy a mounting grommet for that size and then drill a 1/4 inch hole in the metal behind the apple logo. To locate the hole you should remove the front cover, remove the apple logo, and replace the front panel without it. You should indent the center of that area with a centerpunch or a pointy phillips screwdriver and a hammer (Don't worry, the steel of any decent screw driver is many times harder than the soft sheet metal of your G3/G4 case.) You should remove the front cover before drilling and also you should consider that some small metal shavings will fall inside your machine if you aren't ready to catch them. Have a friend hold a paper cup under the drill site while you drill. To drive the LED, do _not ever_ hook it up to the power supply directly or it will light very very brightly for about 1/10 of a second and get very hot. You have 2 choices. If you want it on all the time, wire the LED into the 5V supply with a 100 ohm resistor in series to limit the current. Or, if you have a SCSI card or hard drive with and LED output, you can simply hook it up to that. LED's are polarity sensitive, but it won't hurt them if you hook them up backwards. Be sure to consult the directions that came with your LED as they are not all created equal. If your LED only comes with a maximum current rating you can calculate the resitor value algebraically using the formula "voltage = current X resistance" Since you know the voltage of your supply is 5V and you know the maximum current rating of the LED, calculating the resistance is simple. Don't be surprised if you can't find the precise value of resistor you calculated, just be sure to buy the next highest value rather than the next lowest. If you can't find a proper resistor you can run the equation again using the 12V supply. If you're still stuck you can get creative by putting resistors in series and adding thier values or putting them in series and dividing thier values. Make sure to test the resistance with a meter before trying the circuit if you are not experienced in calculating complex resistor values. Also, you should run the formula again and calculate the current flowing through your resistor to be sure that you don't smoke it either.

 

 

Think REALLY Different

 


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