Replacing the DC PSU

Discussion in 'Sega Dreamcast Development and Research' started by Rocky5, Sep 26, 2014.

  1. keropi

    keropi Familiar Face

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    Nothing has a price similar to the worth of raw components , nowhere in the industry. Be sure that the chinese clones use the cheapest components possible or even worse replacement components that try to "do the same job" in most cases, cost cutting everywhere. The 20GBP "picopsu" has 3-4gbp worth of components, most likely the real pico has components worth more than 20gbp on it, genuine stuff no matter how small are expensive. At any rate, I'm dropping this as there is no point really :)
     
  2. nonosto

    nonosto Intrepid Member

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  3. Nopileus

    Nopileus Rapidly Rising Member

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    Get the original minibox 80w picopsu, they're like 25 *insert local currency*.
    Add a Wii power brick from ebay for ten bucks and solder on a 5x2.5mm barrel jack and you're set. 12v 3.7A, high quality and readily available, just make sure it's not a chinese knockoff.
     
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  4. nonosto

    nonosto Intrepid Member

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  5. AndehX

    AndehX You got boost power!

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    Ok, problem solved.

    So it turns out that the Y splitter I was using for my Dreamcast and Saturn (so I can use the same DC adapter on both) wasn't making a proper ground connection to my Dreamcast, but since it was making proper connection to my Saturn, there was still a ground connection there, but it was causing some insane interference.
    So the lesson here is: Don't use Y splitters, or if you do, make sure it's making a proper ground connection to BOTH consoles.

    The PicoPSU and DC adapter I was using, are perfectly fine...
     
  6. nonosto

    nonosto Intrepid Member

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    My idea is to solder this cable to power switch to replace the old grey cable:

    https://www.alibaba.com/product-det...ml?spm=a2700.7724838.2017115.1.16260f49AuSeJv

    I would like to use it like power cable,is it possible for this pico, is it the right plug?

    [​IMG]

    Another thing, about parts link from Collingall. It's very expansive for shipping to Europe, I must found other provider.
    I found this for molex 6 connecor is it good?

    http://www.ebay.fr/itm/CONNECTEUR-M...hash=item4b02fa54fe:m:mN7qFwgOvrKbT3paQWS2GXw

    THX
     
  7. Collingall

    Collingall Robust Member

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    The port you have circled is an additional power output port, I believe that it is for the extra P4 power on PC motherboards, you wont be able to use if for the power switch. If you plan on cutting the wire for the power switch anyway you can cut one of the wires going to the DC Jack plug and solder the power switch wire across that.

    The item you linked looks like the connector the Dreamcast uses so it should work just fine.
     
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  8. retronerd

    retronerd Spirited Member

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    I have a strange problem, this is on a saturn. when i turn it off and on i have to vait some seconds before it turns on again.

    https://imgur.com/a/ryOfo

    shall i maybe wire the power switch differently?
    [​IMG]
     
  9. AndehX

    AndehX You got boost power!

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    Nope, thats normal. both my PicoPSU's do this also. I don't think there's any way to fix it.
     
  10. retronerd

    retronerd Spirited Member

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    OK thanks!
     
  11. Korn16ftl3

    Korn16ftl3 Robust Member

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    So I'm going to go the pico route for my dreamcast mostly so I can supply all kinds of LED's as well as a full sized hard drive from within the console. I plan on doing the ide mod with an ide to sata conger mounted right in the console. I'm going to link the pico I bought and the power brick I'm considering and hopefully you guys will have some feedback and be able to tell me it seems sufficient for this project (I'm guessing it's quite a hit overkill but I commonly do that when it comes to a psu anyways)

    Power brick:
    12V 8A 96W AC/DC Power Adapter with 5.5x2.5mm DC Plug and 2.1mm https://www.amazon.com/dp/B01MZGNJA5/ref=cm_sw_r_cp_apa_Lb55zbGKPAFW6

    The pico that is on the way (pretty sure it's the same one I see in a lot of your photos/projects):
    http://www.ebay.com/itm/111919067480
     
  12. nonosto

    nonosto Intrepid Member

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    Hello world
    I have a special issue: after off the console my fan run always, but when I use the original PSU, no problem. I measure 2,373 V in 5V pin and 0,362 V in 3V pin on OFF position.
    Do you know why?

    Another question: I would like use a connector for power switch cable:

    [​IMG]

    What kind connector can use for this and wired it.

    [​IMG]

    THX
     
  13. nonosto

    nonosto Intrepid Member

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    For the ON/OFF I use this plug:

    [​IMG]
     
  14. Nopileus

    Nopileus Rapidly Rising Member

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    You should splice the power switch into the 12v input on the positive wire. The PS_ON pin should be hard wired to ground.
    If you switch the PS_ON signal you'll see funky behavior like the system not turning off fully, lights staying on and the like. In fact if you jump back a couple tens of pages you can see me having similar issues.
     
  15. Korn16ftl3

    Korn16ftl3 Robust Member

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    Do this as mentioned earlier in this thread picopsu_1.png from what I've read here running the power switch the way you have it does not completely turn the power off to the system and had unwanted effects like you are experiencing
     
  16. -=FamilyGuy=-

    -=FamilyGuy=- Site Supporter 2049

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    Yeah picoPSU are designed for PC motherboards, so there are still some power delivered even when it's OFF, for power-on-lan, etc.
     
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  17. nonosto

    nonosto Intrepid Member

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    THX I understand my error... I conect ON/OFF directly from power switch. Do you have any idea for make it properly with nice conector?
    One thing, battery charge only ON position? not OFF like officila PSU.

    The + wire is the white on PICO?

    [​IMG]
     
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  18. Nopileus

    Nopileus Rapidly Rising Member

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    The battery doesn't charge with the original PSU either if it's turned off, the power switch directing switches the mains input AFAIK.
    If you don't play the system for a long time it'll be flat, that's just the nature of it.

    White should indeed be the positive wire.
     
  19. Korn16ftl3

    Korn16ftl3 Robust Member

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    So I have seen people using the same setup for a saturn but they are able to switch the psu on and off using the ps_on linked to ground to turn the system on and off, the only real difference I'm seeing I'm the wiring tho os they are using the power from the hard drive set of wires rather than the motherboard molex set, would this make a difference at all in the weird behavior others go by wiring using the ps_on to gnd?

    Further food for thought, I recently modd'd my saturn with a region free bios and the FRAM mod so my save data no longer requires the coin battery to keep. This causes the RTC setting screen to show up at random on start up which is rather annoying but hey my game saves are safe. I started thinking about the 5v standby power on a psu and downstepping it to 3v like the coin battery this would keep the rtc active as long as the system is plugged in and no need to reset it randomly on start-up.

    Any feed back on that idea? As far as I can think as long as I do not switch the main power on and off with the switch and can use the ps_on to ground method it should work just fine.
     
  20. Xerxes3rd

    Xerxes3rd Rapidly Rising Member

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    Does switching the PS_ON pin to ground through the normal DC power switch work if you remove the blue MOV that's wired to the DC's power switch? I suspect most people leave the MOV there.

    I'm not sure there's a way to power the RTC/battery circuit without powering the rest of the 3.3v components. You'd probably want to look through the motherboard schematics and see what else is connected to the 3.3v that the RTC/battery to ensure the DC won't be drawing too much current from 5v standby. If there are other things connected, you might be able to cut a trace somewhere, then power the RTC/battery yourself.
     

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