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Thread: PW60 In-car regulation

  1. #11
    Variable Bitrate
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    Yes and yes. 494 and a potmeter 50K. That coil is from an old PC PS.

  2. #12
    Constant Bitrate will_santana's Avatar
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    DAMN!!!!
    Started quoting the IC's down here in Brazil. The TL494 and UC3843 are SO cheap! I'm glad to see there's a easy and affortable solution for my case.
    The TL494 is cheapper, but the cost of UC3834 is not an issue at all

    I think I'll go with bbalazs desing just because it looks simplier than evan's one.

    Any special recomendation about that coil or can it be any PSU coil, bbalazs? I got a LOT of broken PSUs that I can savage for the coil or any other component needed. What's the other IC close to the 7812? I think it's the handwriten one in the schematic and it's kinda hard to read. The old printed value is BD246C. So I guess it's a transistor, but can't read the codes.

    I think I'll need you guys to help me with tracking the 12v rail and the cut point in the PW60 itself. Just tooka quick look and couldn't find the switch IC. I'll look better and if still can't find it, I'll post some hi-res pics for you.

    Forgive me for this much questions, but I'm really bad with analog desing (more the digital design dude myself)

    Thanks a lot for the info and glad to see that there is good and competent people like you guys around!

    []s

  3. #13
    Variable Bitrate
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    My circuit works with the smaller 'choke' coil (or how it is called) of the ATX DC side. As I remember it was a 250W PSU.

    I had to try and try, because I had no scope at all. Just two cheap multimeters. First I set the output voltage, and then I used the other one to measure the current on the primer side. I applied pure ohmic load on the secunder site. I was searching for the situation, when efficiency goes over 90%, that was enough for me.
    You can also play with the oscillator freq (by resistor and capacitor).

    Or ask a friend who is an electric engineer/techician or can calculate and measure the inductivity of that coil.

    One of the black cube is BUK456 FET, the other one is the Schottky diode.
    Sorry misleading you, there is no 7812 stabiliser yet. This circuit was just for test. I also use it, when I need higher voltage sometimes.
    That thick wire behind is the 0,01 Ohm resistor to limit current.
    Instead of transistor I used BUK456-60A FET, but you can use any recycled transistor for heavy load (5A or so). As you can see I also applied recycled capacitors....

    Take care to form the common ground point (I suggest star-order), because current over some amperes cause weird things flowing 1-2cm...not the same than in the realm of computers...

  4. #14
    Constant Bitrate will_santana's Avatar
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    thanks for the fast reply

    I'll do this (for the whole community benefit):

    Take your schematic and put it in some software I got. Make a one-sided PCB with discrete components (SMD can be very tricky and hard do find and/or deal with)
    Then I'll post the PCB for your aproval and changes it will need

    Once it's done, then will be the time for the PW60 modding.... but that's another history!!!

    []s

  5. #15
    Variable Bitrate
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    Will, if you know, how much I hate to drill ) Therefore I used those smd components. They are also cheaper and easy to identify. Not bothering to check those silly color-code...

  6. #16
    MySQL Error MatrixPC's Avatar
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    You figure out a method of doing it, I just suggest doing a little different way.
    You build a 12V regulator with the part posted.
    Modify the PW PSU you already have.
    Instead of doing what evandude method, try this one. I am not sure if it work, but it should and easier.
    How about doing it this way.
    Buy a 20 PIN atx extension.
    Cut the 12V wire on the extension.
    Use the output from the PSU (cut wire)to trigger/turn on the DIY 12V regulator. You don't have to use it, or you have to find a way to power the regulator the same time as the PSU.
    Feed the regulated 12V to the other end of the cut wire to the extension which feed the mobo.

    Connecting the wire is much much easier than solder and de-solder the IC legs.
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  7. #17
    Constant Bitrate will_santana's Avatar
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    Quote Originally Posted by MatrixPC View Post
    You figure out a method of doing it, I just suggest doing a little different way.
    You build a 12V regulator with the part posted.
    Modify the PW PSU you already have.
    Instead of doing what evandude method, try this one. I am not sure if it work, but it should and easier.
    How about doing it this way.
    Buy a 20 PIN atx extension.
    Cut the 12V wire on the extension.
    Use the output from the PSU (cut wire)to trigger/turn on the DIY 12V regulator. You don't have to use it, or you have to find a way to power the regulator the same time as the PSU.
    Feed the regulated 12V to the other end of the cut wire to the extension which feed the mobo.

    Connecting the wire is much much easier than solder and de-solder the IC legs.
    that's a good damn idea, matrix
    I've bought a ATX extension with the power suply and planned not to use it to keep things clear inside the box, pluggin it right into the mobo
    with your idea, i can just cut the 12v line (only one on atx conector), put it as regulator input and then solder the regulator output back on the atx extension! I think it might work
    This will not lower the power demand on the input and keep things nice and clear

    Maybe build a doughter board with some old broken modos ATX female conectors i have and the atx cables from one of many death ATX PSUs I got too

    once more, thanks guys
    I'll keep you updated with the things

    []s

    Quote Originally Posted by bbalazs View Post
    Will, if you know, how much I hate to drill ) Therefore I used those smd components. They are also cheaper and easy to identify. Not bothering to check those silly color-code...
    hehhehehehehehehhe
    drilling PCBs is really boring
    but SMD components are a little hard to find in my city
    maybe I ask for some when I order the TL494. That will be my first SMD PCB. Hope I don't burn anything or get electrecuted

    Kidding. As said before, I'll keep you guys updated

    Thanks
    []s

  8. #18
    Constant Bitrate will_santana's Avatar
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    hi, guys!!!

    back from ashes!

    the carputer project is almost done
    just finishing my custom RR skin and the only one thing that gonna last is the PSU

    so, i've been thinking a lot about it
    I'm having some trouble finding some parts down here in brazil. so i'm trying to make it the simplier the possible.

    i got a lot of pic controlers here, the programmer, software and skills to use it.
    what I thought was:

    1 - connect the PSU straight to the car battery (car power line) when the ignition is off
    2 - use a LARGE capacitor or a spare battery to keep computer alive during engine start
    3 - connect the PSU to some sort of large 12v linear regulator when the engine is on
    4 - monitor the input voltage to the regulator so if drops bellow 13v (hi power demand or alternator fail), so the computer powers down or go straight to the battery again (not so smart but necessary in some cases and skips the voltage drop in the regulators)

    the system could be switched by a relay conected to the ignition AND the pic controller

    so, what you PSU masters think about it? would it work?
    how to make some kind of 6A linear voltage regulator (7812s barelly can handle 1a and parallel grid is not good for it)?

    []s

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