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Help, trying to convert AC monitor to use DC.

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  • Help, trying to convert AC monitor to use DC.



    I'm trying to run my dell 15" lcd off DC current. I was told I should be able to bypass the monitors PSU and connect DC. Can anyone help? I need to identify the PSU and check what voltage it outputs with my multimeter. I wish I would have finished my EE degree.

  • #2
    That's one way to do it. The other way is to buy and inverter and power it from that. Loads easier if you don't know what you're doing.
    Originally posted by ghettocruzer
    I was gung ho on building a PC [until] just recently. However, between my new phone having internet and GPS and all...and this kit...Im starting to have trouble justfiying it haha.
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    • #3
      Already have an inverter. Horrible buzzing. I'm about to buy a dc-dc power supply for pc. Would love to run monitor off DC as well.

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      • #4


        Am I way off?

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        • #5
          another thought, if that IS the dc out, would grounding the (-) improve the buzzing when running through an inverter?

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          • #6
            Not the DC out.. Don't ground that.
            Christmas Car Project 2008

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            • #7
              That spot you circled is the bridge rectifier. It is where AC is converted to DC but that is not the regulated DC out. What is the voltage you read there when the monitor is on?

              There is also a good possibility that several different DC voltages are required. It looks like there is more than one regulator after the bridge.
              ~Jimmy

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              • #8
                I will check the voltage when I get home. Thank you very much for your help. And thank you for not flaming, I know I sound like a noob.

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                • #9
                  I know Jack about electronics, so this diagram is worth what you paid for it. I'm not responsible if my ignorance burns up your display card and power supply. Maybe someone else can comment on what's wrong in the picture.

                  Find out what kind of voltage is coming out of the regulator. Is it just one voltage or two? I think maybe just one because of what looks like transformers downline. If it is just one type of voltage, you can supply that voltage where it comes out of the rectifier.

                  Of course, once you start unsoldering the rectifier and replacing it with your stuff, the process is pretty much irreversible. You'll either get it to work, or it will become a doorstop.

                  You might want to check and see where the inverter is getting its power from. If it is from the AC input, you are also going to have to figure out how to supply or replace the inverter. And be CAREFUL around the inverter! It jumps power up to the thousands of volts range to run the CCFL tubes. Even getting close to the transformer over there can cause you to get a nasty shock.
                  Attached Files
                  Originally posted by ghettocruzer
                  I was gung ho on building a PC [until] just recently. However, between my new phone having internet and GPS and all...and this kit...Im starting to have trouble justfiying it haha.
                  Want to:
                  -Find out about the new iBug iPad install?
                  -Find out about carPC's in just 5 minutes? View the Car PC 101 video

                  Comment


                  • #10
                    So if I understand correctly, the power is rectified to dc and then converted to two different voltages using the regulators? So I would want to find the voltage after the rectifier and feed it what it wants and let it regulate that current into whatever it needs? Also, if I do F up this board, I can replace it for $30.

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                    • #11
                      Originally posted by digitalmayhem View Post
                      So if I understand correctly, the power is rectified to dc and then converted to two different voltages using the regulators? So I would want to find the voltage after the rectifier and feed it what it wants and let it regulate that current into whatever it needs? Also, if I do F up this board, I can replace it for $30.
                      The regulators keep the power from exceeding a certain voltage limit. The transformers are what steps it up/down.

                      It looks like the transformers are after the rectifier and before the regulators. If true, that means a single DC voltage is supplied and then stepped up/down by the circuitry so you could theoretically feed it a single DC voltage and it would work.

                      *IF* I am right. Which I may not be.
                      Originally posted by ghettocruzer
                      I was gung ho on building a PC [until] just recently. However, between my new phone having internet and GPS and all...and this kit...Im starting to have trouble justfiying it haha.
                      Want to:
                      -Find out about the new iBug iPad install?
                      -Find out about carPC's in just 5 minutes? View the Car PC 101 video

                      Comment


                      • #12
                        So I do want to check the voltage at where I labeled as "dc out" at the positive and negative terminals?

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                        • #13
                          Originally posted by digitalmayhem View Post
                          So I do want to check the voltage at where I labeled as "dc out" at the positive and negative terminals?
                          Start there. If it is 12V you are golden. That is not likely. Chances are it is a fairly high DC voltage so be careful. The clue about that is that the nearby capacitor is only 100uF but at 450V. Be careful not to get your fingers in there, it may bite!
                          ~Jimmy

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                          • #14
                            It read 165 volts before my dumbass tried to measure the amps and blew the fuse on the board. I'm an idiot.

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                            • #15
                              The ammeter creates a short across the leads. It's almost the same as just taking a wire and shorting out two points. Don't do that.
                              Anyways, here's what I think the different parts are. Everything that I pointed out is an AC component except for the regulator and the rectifier... That I'm thinking that since there are voltage multipliers on the board, that the backlight may run on the AC.
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