@johnmckee we really would need to know the exact panel number that you are dealing with. Narrow down the iMac model where this comes out of. If you still have the logic board, add images of that as well.
Commonly, your LED backlight goes through a boost circuit and you should have between 25V-40V on that complete circuit. That is not to say, you can apply that voltage to the individual channels of your backlight. Again, we have to say common, because we do not yet know which setup you are having. Your backlight is divided into two bar's. Each one of those is for the different strips. Your image 2 shows the 6 connectors per bar, drives 3 sets of LED's. It looks something like this
[image|1325569]
Anode being positive and cathode being negative.
Do not simply go and blast some voltages into those. It'll burn out your strips. Get a bench power supply and use it to drive one channel. Start a 3V (yes it's low, but it's safe) and increase the voltage in small increments. You are not going to achieve full brightness across the screen but only a partial illumination. Once you identify the max brightness for that channel, you know the voltage you will need for all the other channels as well. Ultimately, I'd opt for a commercially available, multiple channel LED driver. Scan place like ebay, alibaba, amazon etc. for some ideas. I am not endorsing any of those places but it's a start.
It will help to see where the connectors plugged in so we can identify pin 1 and the individual channels. Looking at the connector and a few different schematics, Black appears to be cathode and Grey the anode. That needs to be verified.
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Just in case you really want to know how Apple drives the circuit :-)
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Just in case you really want to know how Apple drives the circuit :-) which is really irrelevant to your project but FYI only ¯\_(ツ)_/¯
@johnmckee we really would need to know the exact panel number that you are dealing with. Narrow down the iMac model where this comes out of. If you still have the logic board, add images of that as well.
-
Commonly, your LED backlight goes through a boost circuit and you should have between 25V-40V on that complete circuit. That is not to say, you can apply that voltage to the individual channels of your backlight. Again, we have to say common, because we do not yet know which setup you are having. Your backlight is divided into two bar's. Each one of those is for the different strips. Image 2 shows the 6 connectors per bar, drives 3 sets of LED's. It looks something like this
+
Commonly, your LED backlight goes through a boost circuit and you should have between 25V-40V on that complete circuit. That is not to say, you can apply that voltage to the individual channels of your backlight. Again, we have to say common, because we do not yet know which setup you are having. Your backlight is divided into two bar's. Each one of those is for the different strips. Your image 2 shows the 6 connectors per bar, drives 3 sets of LED's. It looks something like this
[image|1325569]
Anode being positive and cathode being negative.
Do not simply go and blast some voltages into those. It'll burn out your strips. Get a bench power supply and use it to drive one channel. Start a 3V (yes it's low, but it's safe) and increase the voltage in small increments. You are not going to achieve full brightness across the screen but only a partial illumination. Once you identify the max brightness for that channel, you know the voltage you will need for all the other channels as well. Ultimately, I'd opt for a commercially available, multiple channel LED driver. Scan place like ebay, alibaba, amazon etc. for some ideas. I am not endorsing any of those places but it's a start.
It will help to see where the connectors plugged in so we can identify pin 1 and the individual channels. Looking at the connector and a few different schematics, Black appears to be cathode and Grey the anode. That needs to be verified.
Just in case you really want to know how Apple drives the circuit :-)
@johnmckee we really would need to know the exact panel number that you are dealing with. Narrow down the iMac model where this comes out of. If you still have the logic board, add images of that as well.
Commonly, your LED backlight goes through a boost circuit and you should have between 25V-40V on that complete circuit. That is not to say, you can apply that voltage to the individual channels of your backlight. Again, we have to say common, because we do not yet know which setup you are having. Your backlight is divided into two bar's. Each one of those is for the different strips. Image 2 shows the 6 connectors per bar, drives 3 sets of LED's. It looks something like this
[image|1325569]
Anode being positive and cathode being negative.
Do not simply go and blast some voltages into those. It'll burn out your strips. Get a bench power supply and use it to drive one channel. Start a 3V (yes it's low, but it's safe) and increase the voltage in small increments. You are not going to achieve full brightness across the screen but only a partial illumination. Once you identify the max brightness for that channel, you know the voltage you will need for all the other channels as well. Ultimately, I'd opt for a commercially available, multiple channel LED driver. Scan place like ebay, alibaba, amazon etc. for some ideas. I am not endorsing any of those places but it's a start.
It will help to see where the connectors plugged in so we can identify pin 1 and the individual channels. Looking at the connector and a few different schematics, Black appears to be cathode and Grey the anode. That needs to be verified.
+
+
Just in case you really want to know how Apple drives the circuit :-)
@johnmckee we really would need to know the exact panel number that you are dealing with. Narrow down the iMac model where this comes out of. If you still have the logic board, add images of that as well.
Commonly, your LED backlight goes through a boost circuit and you should have between 25V-40V on that complete circuit. That is not to say, you can apply that voltage to the individual channels of your backlight. Again, we have to say common, because we do not yet know which setup you are having. Your backlight is divided into two bar's. Each one of those is for the different strips. Image 2 shows the 6 connectors per bar, drives 3 sets of LED's. It looks something like this
[image|1325569]
Anode being positive and cathode being negative.
Do not simply go and blast some voltages into those. It'll burn out your strips. Get a bench power supply and use it to drive one channel. Start a 3V (yes it's low, but it's safe) and increase the voltage in small increments. You are not going to achieve full brightness across the screen but only a partial illumination. Once you identify the max brightness for that channel, you know the voltage you will need for all the other channels as well. Ultimately, I'd opt for a commercially available, multiple channel LED driver. Scan place like ebay, alibaba, amazon etc. for some ideas. I am not endorsing any of those places but it's a start.
It will help to see where the connectors plugged in so we can identify pin 1 and the individual channels. Looking at the connector and a few different schematics, Black appears to be cathode and Grey the anode. That needs to be verified.