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AT to ATX Power Supplies 5

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Kows

Programmer
Dec 15, 2001
11
US
I've got a server case that I just retrofitted with a new motherboard tray. It is an AT case, but very large, enough room for everything... only problem is it has a dual AT power supply. I need to be able to convert it so I can get power to my new mobo.

Thanks in advance!
-Kows
 
Power supply isn't convertable. ATX has different voltages available.
You will be better off buying a new case with power supply. Ed Fair
efair@atlnet.com

Any advice I give is my best judgement based on my interpretation of the facts you supply.

Help increase my knowledge by providing some feedback, good or bad, on any advice I have given.

 
Mounting the ATX power supply shouldn't be a problem but you will have to give it a "SOFT" on/off switch as the physical on/off device on the AT front panel won't work! the ATX power switch just makes and breaks the conection leaving the board to power on.
The other problem is the differant location of all the conection sockets, PS2 keyboard and mouse etc, though sometimes you can use an adapter style plate if you have a removable back panel.It is a little dificult giving advise without physically seeing the case but I hope I have been of some assistance. Martin Vote if you found this post helpful please!!
 
A question for "paparazi": I think I have the same issue that you just responded to on converting an AT case to ATX. I have purchased the ATX supply and am getting 3.2v to my power supply pin. When I connect a switch (essentially shorting the pins) to these pins I get nothing - the system doesn't boot!
What did you mean when you said you need to "give it a "SOFT" on/off switch as the physical on/off device on the AT front panel won't work!"?

 
The front panel switch needs to be of the "momentary" type, rather a permanent "on" or "off" variety. E.g. like the type used for a front door bell.

ROGER - GØAOZ.
 
Interestingly the pictures shown at AYJAYCEE's URLs, depict cables with FEMALE connectors at both ends! Maybe the photos are not true representations of the products, and also no sign of any electronics to provide the required different voltages not normally available in the conventional AT type PSU.

Anyone actually used one of these products, and can comment accordingly?


ROGER - GØAOZ.
 
Well, this is something I am willing to spend > 200 dollars on, it is at least a 1,000 dollar server case.
BTW... the 4 pin connecters are the same, its the mobo connecter that is odd.
 
KOWS, I'm far from convinced that this adaptor will do the job for you... If it was my new mobo, I'd want a cast iron guarantee from the PSU adaptor manufacturer/supplier that his product is going to work and not blow up the board!

There were quite a number of AT boards floating around a year or so ago that had BOTH the AT and ATX type power supply connectors - I am just wondering if this adaptor was meant for them...

Anyone else care to comment?


ROGER - GØAOZ.
 
I understand the feeling. But you will be spending an additional $200.00 to make something that is probably dangerous to your hardware. Far better to rip the guts out of the existing power supply and mount a 300 watt atx supply in there. The low voltage supply in the atx is designed for that, rather that using a higher voltage set and bleeding it down, which also generates heat. Ed Fair
efair@atlnet.com

Any advice I give is my best judgement based on my interpretation of the facts you supply.

Help increase my knowledge by providing some feedback, good or bad, on any advice I have given.

 
First I want to clearify the subject of male and female connectors.

In electronics the terms "male" and "female" refer to the plastic connector not the pins.
The ATX power supply has a male connector because it plugs into the connector on the motherboard, which is female.

The picture of the ATX to AT adapter shows a female connector with some of the pins missing.
This type of adapter is used to connect an ATX power supply to an AT motherboard but not the other way around.

The pins for the +3.3 volt lines are missing because AT power supplies don't have them. The conversion from +5 volts to +3.3 volts is handled by the motherboard's circuitry when the motherboard requires +3.3 volts.

Some AT motherboards have both types of connectors so you can use either an AT or ATX type power supply but ATX motherboards always require ATX power supplies.

Remember, the original AT machines had 5 volt I/O and core voltages.
Because the AT power supplies don't have 3.3 volt lines they won't work on an ATX motherboard.

So kows, in order to use the AT server case you need to replace the power supply and power button like GOAOZ, paparazi, and edfair suggested.

Hope this helps. Good luck.

John
 
I have a related question. I am upgrading an AT computer and have purchased an ATX power supply but unfortunatly won't power up. I checked the voltage from the power supply with the following results. The standby voltage (pins 19 & 9) reads 5.05v (great), however the "power-on" voltage (pins 14 & 4) which should be 5.0v reads 4.28v. Would this cause the Mobo to not fire up????
 
In reply to PSU swop.:There is often a jumper on the motherboard you must change to swop from AT to ATX ?? Check your manual. Martin
Vote if you found this post helpful please!!
 
All right. Thanks everyone, your replys were greatly appreciated. I suppose I'll just have to get a new PSU... I'll tell you how it goes.

Thanks Again,
-Kows
 
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