SomeGuy
Veteran Member
Since the question came up, and there are few good search results, for the sake of any eBayer who has obtained a PC/XT or AT form power supply to sell or is looking to buy one, but is not sure which is which (scale can be hard to determine from some pictures), here are some examples.
First, both XT and AT power supplies use a connector like this:
Clearly it is not an ATX connector. An AT power supply may connect to and power an XT motherboard and and XT power supply may connect to and power an AT motherboard, but the two have different form factors and will not fit in a case designed for the other kind.
This is an example of a generic clone "XT" power supply. It may be used in an IBM PC (5150), an IBM XT (5160), or a generic "XT" clone that uses the same size case.
It measures about 8 1/4" long, 5 1/2" deep, and 4 3/4" high, not including the switch or the raised shielding around the switch.
Note that many clones used their own form factor and proprietary power supplies.
This is an example of a generic clone desktop "AT" power supply. It may be used in an IBM AT (5170) or a generic "AT" clone that uses the same size case. Desktop AT clones may contain 286, 386, 486, Pentium 1, and even a some AMD-K6 motherboards.
It measures about 8 1/4" long, 5 7/8" deep, and 5 7/8" high, excluding the switch, but including the "overhang". This style of power supply leaves an area at the bottom that allows a full sized AT motherboard to extend underneath it.
Note that power supplies for later tower-style systems do not have an attached switch. Again, note that many clones used their own form factor and proprietary power supplies.
Third party power supplies were common upgrades and replacements in genuine IBM equipment, and generic form XT and AT power supplies were common in full-sized XT and AT desktop clones.
Thankfully, neither have rainbow-LED lit fans.
First, both XT and AT power supplies use a connector like this:
Clearly it is not an ATX connector. An AT power supply may connect to and power an XT motherboard and and XT power supply may connect to and power an AT motherboard, but the two have different form factors and will not fit in a case designed for the other kind.
This is an example of a generic clone "XT" power supply. It may be used in an IBM PC (5150), an IBM XT (5160), or a generic "XT" clone that uses the same size case.
It measures about 8 1/4" long, 5 1/2" deep, and 4 3/4" high, not including the switch or the raised shielding around the switch.
Note that many clones used their own form factor and proprietary power supplies.
This is an example of a generic clone desktop "AT" power supply. It may be used in an IBM AT (5170) or a generic "AT" clone that uses the same size case. Desktop AT clones may contain 286, 386, 486, Pentium 1, and even a some AMD-K6 motherboards.
It measures about 8 1/4" long, 5 7/8" deep, and 5 7/8" high, excluding the switch, but including the "overhang". This style of power supply leaves an area at the bottom that allows a full sized AT motherboard to extend underneath it.
Note that power supplies for later tower-style systems do not have an attached switch. Again, note that many clones used their own form factor and proprietary power supplies.
Third party power supplies were common upgrades and replacements in genuine IBM equipment, and generic form XT and AT power supplies were common in full-sized XT and AT desktop clones.
Thankfully, neither have rainbow-LED lit fans.