I have a Gateway BTX case w/ a NF4 chipset MB that crapped out. Trying to salvage the system the only other BTX MB I could find was from a HP DC5750. Took a little modification to the heatsink but I got it to fit. The system runs stable, the only issue is when first booting I get POST error for Front USB not detected and always have to hit F1 to continue. The ports are supplying power but won't detect any devices. The board also has a second header designated for Media Card Reader which also does not work though there is no error message for that. I have tried moving IRQ's around, resetting to defaults with no luck. I took ohm measurements of all pins comparing them to a known working system which seem to check out so I don't think it's the chipset. So a couple of questions...
How can the MB detect when the USB header is connected. Does HP use a special termination circuit to signal the MB for this? Is it required for them to activate?
Also the CPU fan always runs at max. There is a setting in BIOS to set the minimum but that has no effect and I have tried several PWM fans with the same result. My temps are 30 idle and 60 under load so it's not a cooling issue. I currently have the CPU hooked up to the Chassis fan, also a PWM connector, and that works fine. This is not a big issue but I'm open to any insights on this.
At first thinking I got a defective board I even ordered a second one from a different reseller (thankfully they were cheap) and I still have the same issue. And BIOS has been flashed w/ latest update. I have been at this nearly two weeks now and read all the manuals.
Please only reply if you have insight on this system. Comments and reviews are not helpful.
To answer my own question. The USB signal is made by jumpering the Ground and S-Ground (pins 8 & 10). Both USB headers work fine after this. The jumper is only required on the Front USB header. Still no idea about the CPU fan issue.
Did the replacement HP board come with the CPU heatsink retaining bracket? The post screws don't line up with the Gateway case. I tried just using nuts at first but it caused the board to flex putting a strain on the CPU socket solder joints making the system unstable. I ended up using one from another hp case (409302-001, 15051-T1-REV A) and cutting out a section of the gateways back panel.