For anybody trying to get the Videomate Compro S350 DVB-S card working in Mythbuntu 10.04 you might not be having much luck if you are running the newer variants which detect as the T750. There seems to be a GPIO issue which causes the card to not send LNB voltage. The quickest way to test if your lnb is getting voltage is with a sat-meter or voltmeter.
If you find that you are not getting voltage you can be grateful that an easy fix is available, you simply need to compile the latest drivers and install them to fix the issue with your Compro s350 not providing voltage to the LNB
Drop down to the terminal and install mercurial if you don’t already have it installed by running
$ sudo aptitude install mercurial
Run the following command to fetch the vdr source code
$ hg clone http://linuxtv.org/hg/v4l-dvb
There seems to be a problem with the current set preventing firedtv from compiling so edit the following file and change the option from m to n on the line for firedtv
$ nano ./v4l/.config
Compile the drivers, this could take a while depending on your hardware
$ make all
If everything completes correctly you can install the patches and reboot
$ sudo make install
$ sudo reboot
After the reboot you should be getting Voltage to you LNB or sat meter now, once again verify by using a voltmeter or sat-meter on your Compro S350. I am not sure if the problem exists on other comprousa cards but if you are having problems similar to the s350 voltage issue it is worth investigating.