Am I seeing this right? I have a handful of 3mm blue LEDs and a few 5mm blue LEDs. I thought I would replace the LEDs in both of my CD-ROM burners. Well lo & behold, in the first one the 5mm LED is stitting in a L-shape holder that is soldered into the board wtih 3 prongs. The LED itself will not come out of the holder. On the other burner, the LED is a 3mm, but it too has three prongs (no holder--just 3 prongs soldered into the board). Now...it's been awhile since I've gone inside a drive like these, but since when did they start using 3-pronged LEDs?? I've never heard of this. Should I get ready to smack my forehead and say "DOH!"?
hi Bistro, The three prongs mean its a tri colour LED, effectively its 2 different coloured LEDs in parallel with a comon cathode. This is so the CD Drive can have one colour when its reading, one colour when its writing, and maybe a third colour (both LEDs on) at another time. If you want to replace the LED there are 2 options, either just have 1 colour, and therefore just one status indicator, or....carefully solder 2 3mm LEDs into the position sharing one of the solder pads, just make sure you get polarities the right way round! I hope thats helpful, RoB
an other thing you can do is solder 2 leds inside the drive and let them shine on some 3mm fiber optic which you stick in the hole in the bay-cover
That's the odd thing...both of these drives are fairly new, but I haven't really noticed any color differences when the LEDs are on. Perhaps they used LEDs that turn from yellowish-green to greenish-yellow.... I probably would like to replace with the two-prong blues. Do I skip over the center contact in this case?
NO! well, probably not. The centre pin is usually the cathode, or negative leg. First off id say check on the circuit board the LEDs are connected to, they often have a diagram of what the bits are, or at least some sort of printing on them showing how things are wired up! The most likely is going to be connect the 2 megative legs of your leds together, and connect them to where the centre pin was, and the positive legs to where the two outer legs where. If you have access to a multimeter you should be able to work it out with that. If youre feeling particularly no fear, id just wire up the new LEDs like i say to above and see if it works! If it doesnt, one or both of the LEDs is connected teh wrong way round...... but im quite cavalier like that... ..and wouldnt reall recommend it cos i dont want to get sued! RoB
Not sure if I am understanding you correctly here. The LEDs I am using are 2-prong only--cathode and anode. What do you mean by "2 negative legs" and the "positive legs"?
sorry, i mean if you just connect 1 LED to the where the old one was, it wont neccesarily light up whenever the old one would have done. So you need to use 2 new LEDs, one to replace each of the LEDs in the old 3 prong LED. The negative leg of the 3 prong LED is really both negative legs from the LEDs inside it. So when you replace it, you need to connect both the negative legs from your 2 new 2 prong LEDs so that they can both light up as needed. Does that make more sense? Basically, the 3 prong LED, really has 2 LEDs in it, so when you replace it, you need to use 2 LEDs, connected together in the same way. have a quick look at this post about half way down theres some info on LEDs RoB
ok, if you are going to hook up 2 leds up to a 3 prong leg thingy, do it like this. The led's both have + and - legs. use a multimeter on the curcuit board when its on to see which 2 are positive and which is -. Ground (-) both of the led's into the -(ground), and have the other two legs to the other 2 +'s. Code: X's are the 3 spots on the circuit to connect to. X(+) X(-) X(+) \ /\ / \+LED-/ \-LED+/
once again my mad notepad killz come to the rescue. if you can't understand it from that, then i suggest you do not try it.
OHHHHHHHH..... Duh....I get it. But next time, diskreet, could you make it so i can color it with my crayons? Thanks all for the help---was doing a search of LED companies in a vain attempt to find BLUE bi-polar 3mm and 5mm LEDs (3-prong). Found one that has a 5mm that goes from blue to green...that might be OK....not sure. But the plextor takes a 3mm LED--none available that are blue/green...would have to go all blue with the two (hey...I remembered your diagram!) LEDs.
although you could use one blue and one green, and wire them up like the diagram....if thats what you are after! Hope it all goes well! RoB
technically you can just buy a 5mm blue/red LED from here and file it down to 3mm. but if you want all blue nevermind.
