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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: theformula on June 28, 2008, 04:55:43 PM
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HI I am building a tower at the moment and I am running my cd drive and floppy drive from an ATX PSU. I am running the psu by shorting it with the green and black wire. I want to be able to switch it on from the front of the tower. I have tried with the wires and the switch provided with the tower. The problem with this is i have to hold down the switch to keep the psu powered. I want it to work normally so I just press it once and it stays powered then press again and it stops powering it.
I was also wondering is using the black and green wire good for this or are they other wires? Will mediator work with the black and green wire used ?(as I am getting one soon).
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theformula wrote:
I want it to work normally so I just press it once and it stays powered then press again and it stops powering it.
I imagine you would need some circuitry to achieve that. This is normally handled by the motherboard (with an ATX compatible board) which is why the momentary switch can switch the machine on and off without the switch needing to latch. You could either look for a schematic to build a circuit to achieve this, or you could replace the switch on the tower with a latching one which can switch mains voltage and current, leave the PSU hotwired, and just switch the mains.
theformula wrote:
I was also wondering is using the black and green wire good for this or are they other wires? Will mediator work with the black and green wire used ?(as I am getting one soon).
Pin 14 switches the PSU on while shorted to ground. That's all you need to do to make it turn on. As long as it is connected to any ground pin it will be fine.
You won't need to do it with the Mediator as long as it has an ATX connector. The momentary power switch on the tower will connect to the Mediator and will work properly with the PSU.
If the Mediator you get is an older one with only an AT power connector, you will need to either replace the PSU with an AT one or convert the ATX one to AT.
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Thanks for the speedy reply. I think i will leave it hotwired until I get my mediator ( I am right in thinking the mediator supplys the mobo so no need for two power sources?).I am gonna go for one with an atx plug. You have cleared up all my main questions in one post. Thank you indeed kind sir :-D
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theformula wrote:
( I am right in thinking the mediator supplys the mobo so no need for two power sources?).
Yes. The power is connected to the Mediator, and the Mediator supplies power to the Amiga through the expansion slot. The power switch is connected to the Mediator which handles the logic of turning the PSU on (and keeping it on) and off when you press the momentary power button.
theformula wrote:
I am gonna go for one with an atx plug. You have cleared up all my main questions in one post. Thank you indeed kind sir :-D
No worries mate!
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the mediator 1200sx has both types of psu connectors already fitted to the board :-)
i dont know if the z4 med has them?
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This (http://www.amiga.org/gallery/index.php?n=2386) and this (http://www.amiga.org/gallery/index.php?n=2484) is what I ended up building for my A1200D. Not only does it allow the PSU to be controlled from a manual switch, but the PSU can also be switched off from a software poke command.
It worked perfectly, but then it had to be abruptly shelved for reasons shown in the posts.
Just thought it might be of interest, :-D
Hodgkinson.
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Hi,
I thought maybe this link (http://www.ianstedman.co.uk/Amiga/amiga_hacks/Amiga_Power_supplies/body_amiga_power_supplies.html#ATX_PSU) would be useful for you.
Regards,
skipp604