I had a power issue with an Acer PowerSV desktop, when I went to replace the PSU with one I had on the shelf it had a strange connector I had never seen before.
If you click on this link, it will take you to a motherboard diagram of the comptuer in question. The connector is labeled "CN9" and the description in the table for that item is "12V port"
The funny thing is, when I disconnect that 12V port and power on the computer, the CPU fan runs, but the hard drive does not boot up and the monitor remains off - so it is a necessary connector.
What is a 12V port and is it common on new PSU's?
FYI - the connector is square and has 4 holes in the end - two have yellow wires going to them and two have black wires going to them.