Power Supply Question: Brown Wire AKA 3.3V Sensing lead....

[jonnyGURU]

Gotta question about this lead. It is connected to the same pin as an orange 3.3V lead. It is called a 3.3V sensing lead which I would imagine should sense 3.3V load on the board, but wouldn't it sense the 3.3V coming from that orange wire? A little more detail about this lead would be appreciated.

 

[jonnyGURU]

OK... I found this:



<< This signal is used to detect the voltage level of the +3.3 V signal being provided to the motherboard. This allows the power supply to "fine tune" the +3.3 V output in the event of excessive voltage drop between the supply and the components that use +3.3 V. This is more needed for +3.3 V than the other signals probably because CPUs use +3.3 V. (Note that the ATX specification makes this signal "pseudo-optional"; it is by default included in the main ATX connector but can be replaced by a wire in the auxiliary ATX connector. >>



Here's my problem....

I have a high end power supply that doesn't work with the Asus A7M266 motherboard, but does work with every other moterboard I've tried. I'm wondering if it is because the motherboard doesn't use the 3.3V lead on the power supply (Asus boards tend to act like an AT board and regulate the 5V to 3.3) and I'm wondering if the power supply is detecting this lack of load and thus wont POST the PC.

Of course, other Asus boards that have no 3.3V load seem to work, so that pretty much shoots that theory out of the water.

I've called Asus and they're about as usefull as tits on a bull. Any help would be appreciated.

 

[Sundog]

I see your talking to yourself again!





j/k😉

 

[jonnyGURU]

Well, I'm fixing to put a load on the 5V with a pair of 25W 2 Ohm ballist resistors to see if I can get anything. I'm thinking it may be the power supply not getting anything back from the motherboard on the 5V power good. Either this or I'm going to try cutting the +5V standby to see if it helps matters any.