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Attachment 9799So there I was, at my workbench with my '03 Vader ANH, when the electronics case came open. I saw mostly what I expected to see except for this: the wiring going to the string blade, that will eventually go to my LED was labeled positive and negative. On one side of the contacts there are little pluses, and minuses on the other side. I thought I had done my research, but now I'm beginning to wonder. Is my saber different from the other conversions I've seen?
I checked the voltage drop across the string blade and there IS in fact only one power wire going to the assembly. I read a voltage drop of 2.51v. I'll have to desolder the positive lead to measure the current. Does this voltage reading sound typical? I was expecting closer to 4v.
While I do not know that vintage, I might have some ideas:
1. Depending on the voltage source and the connection you have, and the current flowing from the source to the blade, there can be a significant voltage drop on the connecting wires, so that the voltage on your LED sting migth be significantly less. Well, in this case I would expect the board not to work with only ~2.5V due to undervoltage thou...
2. If it's a Vader blade, it has red LED's. They have a lower threshold voltage than blue and green, so the LED's have a resistance in series wo Limit the current. So if you measure directly at the terminals of the LED's, you will end up with ~2.5V.
Quote:
Originally Posted by Obi1
I rechecked the board and blade with my meter and found that there is 4.5ish volts on the board supply but only 2.5v drop across each blade section. That must mean that the voltage drop is happening in the resistors and the sounds. I have seen photos and drawings on the forums that illustrate connecting all of the negative wires and then connecting the led to the board via the led positive and the negative bundle. What does that do to the voltage, if anything? I think it puts all the resistors in parallel and raises the current. I know that guys just DO this, but I want to understand it. Can anyone tell me what voltage and current they ended up with by coming straight off of an MR board like this?