AT pwr supply vs ATX

[ShaggyDogg]

A friend of mine has an old Pentium 133. I was going to look at upgrading it for him (new mobo,processor,etc). I have heard I will need a new power supply since it is an AT not ATX. Is this true? Will any of his peripherals work with the new power supply (ATX) or will I need to replace everything. What is the difference in the two?

 

[Modus]

The peripherals will be fine but the motherboard is the problem.

ATX power supplies use a different motherboard connector and have a different voltage specification. They also don't allow for a "hard power switch" at the front of the case like on AT power supplies. Instead, their power switch connector is wired through the ATX power connector that plugs into the motherboard, and essentially, the motherboard turns on the power supply! (Once it detects a push from the case button.)

The ATX specification also calls for a different case layout to allow for motherboards with I/O connectors attached directly to the PCB. So you'll have to change the case, but the hard drive, CDROM, floppy, etc, will be OK.

Modus

 

[RossGr]

It is hard to but a ATX Mobo in a AT case. Both the connector to the Mobo and the power switch are different. You can change out the power switch, but since ATX Mobos have Parallel/serial & USB connectors on the Mobo it will not fit correctly into a AT case.

The transition from AT -> ATX requiers a new case.

 

[spamboy]

Modus is right on. Just go buy another case with an ATX power supply in it.

 

[ShaggyDogg]

Thanks all! This site is great! I have learned so much from you guys (and gals). I am fairly intelligent and like to try new things....sometimes it's good to have some info from people who have experience though. Saves a lot of headaches and broken equipment!