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auto turn on atx power supply with capactitor


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finally found this again

 

converted to pdf and attached

 

can we sticky this please

 

converted original pdf at 465 kilobytes to djvu, now only 88 kilobytes

djvu reader for windows in a post of mine further down

How_to_automatically_turn_on_an_ATX_motherboard_upon_power-up__t.djvu.zip

Edited by @lien_Zed
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Just to add to this if you use an ATX P/S instead of a switching P/S for your arcade cab and want it to turn on when you power up the cab find the green wire inside the 20 pin plug loom and cut it off at the plug end then just ground it permantly
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i went hunting and found a photo that shows how to force atx power on by modify the wiring of the atx power supply as well. this mod will be great if you use the atx psu to power a car amp for your mame cab

 

photo attached

 

also, check your pc bios there is on newer boards a setting you can change so that it will restart after power loss

atx-mod-pic2.thumb.jpg.403fbecdf94f31db33dd5f2fa327c9d9.jpg

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also went hunting and found a tutorial on how to convert an atx psu in to a benchtop power supply

 

i tried to convert it to pdf, but at 150 dpi it was 8 megabyte in size!!!

 

so i converted it to djvu format instead and the same file is now about 250 kilobyte long

 

get a freeware viewer here

 

http://windjview.sourceforge.net/

 

if u use ubuntu, theres a djvu reader built in to it

the file attached i had to convert to a pdf or the forums would not upload it

 

also attached "the fix"

the fix will describe how to put on a dummy load to the psu to keep it running. some atx psu will not run if a load is not on there and shut down

Converting_a_PC_Power_Supply.djvu.zip

The_FIX.djvu.zip

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thanks this is just what i was looking for :)

 

excellent

 

there was someone else the other day who made a post and wanted to know about auto turn of of atx psu's

 

that was what reminded me to go hunting the net and save it in pdf or djvu for future reference for all of us:)

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The cap trick is a bit different to the green to black ATX power on.

 

To clarify:

 

The cap trick is used to turn on a motherboard/pc without having to press the powerbutton.

 

The "green to black" trick is to power up the power supply without needing a motherboard (to use as a bench supply or an arcade psu).

 

Thanks for posting the cap trick - I had forgotten all about it!

 

~~~~~~~

 

Oh, and the polarity of the cap - why is that important? If it is hooked up backwards, it will heat and then boil internally over time, and then go off like a firecracker :blink:

 

Cheers

Jacob

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~~~~~~~

 

Oh, and the polarity of the cap - why is that important? If it is hooked up backwards, it will heat and then boil internally over time, and then go off like a firecracker :blink:

 

Cheers

Jacob

 

it wont blow up...not enough current for it to do that

 

the capacitor in this case is being used as an "electronic switch" so to speak

 

if wired up back to front,it wont work, plain and simple

 

How It Works:

 

A capacitor's discharged state is shorted. When you apply power to the unit,

the cap acts as a short between the pins, activating the power supply.

 

With 5V flowing through the cap, it's shorted state becomes an open state,

allowing the board to boot normally.

 

When you power down the unit, the capacitor will discharge, and resume its shorted

state, allowing it to do this the next time you power up.

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No offence intended, but what's wrong with PDF?

Just re-distil at a lower quality...

 

 

the big difference between pdf and djvu is filesize

 

djvu uses a lossy format similar to jpeg to save files

 

the picture quality is just as good as pdf, but the file size is usually a hell of a lot less then pdf

 

why bother to recompile documents at a lower quality when you can get almost the same quality and much smaller document size using djvu?

 

last year i spent 6 months scanning and converting over 6000 pages of old computer magazines to pdf format

 

i kept the pdf format and converted the lot to djvu and usually the djvu file come in at under 10% of the original file size with quality just as good as the pdf and uploaded the djvu format to ftp servers in the usa for others to share & use.

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  • 1 month later...
  • 2 years later...

Just noticed this thread.....

 

I might experiment with the Cap method.

I have simply been using an external (to the PC) Startup/Shutdown button inside the cab.

 

But, As I expect the cab to loose power at any time (Someone pulling the plug) the machine does a 'sync' after any games are run.

So I don't really need to worry about using shutdown to powerdown the cab, And startup is simply kicked off by the cap at poweron.

(AND I can still keep the Startup/Shutdown button in place/use for when I want to manually control the mainboard Startup/Shutdown)

 

Nice

Michael.

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  • 1 year later...

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