beige power mac g3 and adb keyboard led questions.

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Joined: Apr 3 2004
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i want to swap out the led's on the power mac g3 all in one that i am hacking. i want to do the front led as well as the led's on the adb keyboard.

in addition i might be switching to a usb keyboard.

the question about all of these are what voltage leds do i need. i would check them myself but the computer still hasn't arrived and i want to have all of my hacking supplies in order before it gets here.

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Joined: Dec 20 2003
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voltage

The stock green LED's have a very low forward voltage (like say 1.2v or even less). I assume you are looking for some exotic colors. So, get the lowest voltage you can find. Hopefully it'll be bright enough. Voltage specs are really for designing current limiting circuits, but your application already has the current limiting stuff built in so you are probably perfectly safe. I would not hesitate an instant to plop any old led in there (except the purple ones).

Dr. Bob

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that makes perfect sense.

i was looking at replacing the stock greens with white ones. now the question is will they be bright enough...i think so...they would be running at about half voltage and if i remember correct the white ones are really bright running at full voltage.

so the next dumb question is...so i just desolder the leads on the stock ones...and then solder in new ones right? anything to be wary of? i know this whole thing is very diy (and i am overcoming some interesting hurdles in this hack) but this is also going to be my wife's computer and i am being very cautious with it (as cautious as someone who is modding a machine can be)

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Joined: Dec 19 2003
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um ... make sure you solder t

um ... make sure you solder the new one on the right way round Wink

TOM

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Joined: Apr 3 2004
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why not the purple ones?

just out of curiosity. because my first choices are either the white ones or the pink ones.(again this hack is for my wife)

the pink ones are like the purple ones in some respects is why i ask.

also do you know what size the g3 all in one uses for the bezel led? and the lights on the keyboard? any idea what size those are...

i forgot what a great resource this site is...you guys have been super helpful.

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Joined: Dec 19 2003
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um the keyboard ones are squa

um the keyboard ones are square ... not sure of the size though ... but standard 3mm round leds should fit no problem ... you might want to mask off between the windows so you dont get too much light overspill between the LEDs ...

TOM

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Re: um the keyboard ones are squa

tomlevens wrote:

um the keyboard ones are square ... not sure of the size though ... but standard 3mm round leds should fit no problem ... you might want to mask off between the windows so you dont get too much light overspill between the LEDs ...

TOM

Varies by keyboard. Most of the ones I've cracked open were round LEDs. As per the purple ones I think they may draw too much current/voltage. I think Dr. Bob made some comments on them in the past. If I were doing it I'd go with the white ones then use a transparent material to color it. You can get a sample book of gels (color filters for stage lighting) for free.

Heres one I saw posted elsewhere:
http://www.rosco.com/main.html
Click on products, color filters, cinegel, then go to the bottom of the page for the link to recieve a free swatch book. I don't have one yet but I've heard they're 2"x4" samples - more than enough to experiment with

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Re: why not the purple ones?

erraticninja wrote:

the pink ones are like the purple ones in some respects is why i ask.

The purple ones have the highest forward voltage, usually around 4.7. The pink ones are actually 380nm "purple" LED's. They look pink because there is no blue in the light output. They aren't very bright because the visible light is only about 10% of their output. The other 90% being invisible UV. Note: it's not a good idea to stare into one of these. Also people tend to overdrive them since they aren't very bright.

Quote:

also do you know what size the g3 all in one uses for the bezel led? and the lights on the keyboard? any idea what size those are...

The front LED is a T1-3/4. Not sure about keyboard. Take one out and measure it. LED's are sized in hundredths of an inch.

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Re: that makes perfect sense.

erraticninja wrote:

i was looking at replacing the stock greens with white ones. now the question is will they be bright enough...i think so...they would be running at about half voltage and if i remember correct the white ones are really bright running at full voltage.

Maybe. maybe not. Hopefully your computer is set up to be a current source and not a voltage source. Then it'll work fine.

Quote:

so the next dumb question is...so i just desolder the leads on the stock ones...and then solder in new ones right? anything to be wary of? i know this whole thing is very diy (and i am overcoming some interesting hurdles in this hack) but this is also going to be my wife's computer and i am being very cautious with it (as cautious as someone who is modding a machine can be)

Don't burn your fingers. The glue holding the trace down will let go if it's hot for too long and you'll lift the pad and that sucks.

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