I have a 6033 E-series board that seems to have all of the analog inputs pegged at -10V with no noise. The board passes the self-test in measurement and automation explorer with flying colors and the DIO channels all work. I have a second 6033 E in the same PC running windows XP and LabVIEW 7.5 and when I change the device number and switch the interface cable to that board all measurements are as expected. I have seen a couple of other posts on this board from as late as December of 2011 with similar issues. My question is: "do you think that the board is dead or is there something else that you'd recommend trying?"
A second question would be: "do you have another newer series that you'd recommend as a replacement?"
Interesting. It sounds like the AI channels are railing at the max 10 V for some reason. Have you tried just shorting one of the channels to ground? It's possible that the channels are just reading a floating signal that is out-of-range for the card. Shorting the channels to ground should bring the voltage down to zero. Also, try taking a differential measurement of a steady voltage source such as a AA or 9 V battery. Another good step to take is to use a different PCI slot in your computer. There is a slight possibility that there is a power issue with your computer's motherboard in this slot, so this may confirm that.
Depending on these steps though it may turn out that the board is shot. If so, there are a few options for a replacement. An M Series Multifunction DAQ card would probably be the most direct replacement. For example, the PCI-6225 is a similar board. It uses the PCI bus, and is compatible with Traditional NI-DAQ and DAQmx 7.5. Using this board wouldn't require too much change in terms of driver and LV compatibility.
However, if you are willing to update LabVIEW and DAQmx to newer versions and if you have PCIe slots available in your computer, the newer X Series DAQ cards offer much more functionality. They offer better timing, DIO and counter functionality, and much higher sampling rates. The maximum number of analog input channels you can get with the X series cards is 32 channels though, so you would need multiple cards if you need a high channel count.
Hopefully this helps!