Brand new motherboard- weird POST issue

I'm building a PC with a brand new Asus Crosshair V Formula motherboard, 8gb DDR3-1333, AMD X6 1100T processor, Samsung 64gb SSD for C: and a 1tb SATA drive for storage. Anyway, when the cable for the front audio on the case is connected, the motherboard will not POST. No video, no beep. As soon as the cable is disconnected, everything is fine. I changed the BIOS setting from "HD" to "AC97" and connected the AC97 connector from the front audio cable and this worked for about 3 or 4 reboots, then it stopped POSTing normally. I'm going to look at a possible BIOS update, but I can honestly say, that after building over 300 systems in the past few years, that this is one of the strangest POST problems I've seen.

Any ideas on why the front cable would prevent the PC from running normally? There's nothing plugged in to the front headphone & microphone jacks, so the cable shouldn't matter whether it's connected or not, right?

Weird :confused

 

Hey, dlb...

That is a strange one - those kinds of symptoms that can make you go nuts...

I wonder if anything is wrong with the jacks themselves - grounding to the case, shorting together, etc...are they built into the case, or are they mounted in an enclosure?

 

I agree with Caliban,you can test them with a multimeter by sticking a couple of pins into the connectors.

AFAIK there is no electrical connection between any of the lines so there's no possible way the motherboard could know the front audio connectors are even there.

 

Thanks for the input, but after going nuts for another hour or two, I updated the BIOS and that fixed the problem. I now have the front audio set as HD with the cable connected and it's survived at least 15 restarts and 5 or 6 cold boots. I was also having a wierd video and SSD issue (the SSD would lock the PC if plugged in to SATA_1 or SATA_2, but not on any other SATA ports, the BIOS flash fixed that too).

 

A lot of newer motherboards do NOT support AC97 connectors on the front panel audio connector, they are HD Audio only. On my case ( Rosewill Armor) the front audio cable has both connectors on the end of the cable but my mobo only supports HD. The AC97 and HD connectors have different wiring.

Sam