3rd party Dreamcast controller not reading VMU's

I have a Madcatz Dream Pad (the original white one) and when I insert a VMU, it powers up for a moment, then just goes dead.
Anyone have any ideas whats going on? I can provide pics, or take a video if needed...

/edit - just realised this might be the wrong forum to post this in. Appologies.

 

ok, it's just randomly started working... I literally have no idea. I took the controller apart, probed around with the multimeter looking for shorts, put it back together, and now it works!?

 

I had a similar problem with an official controller with the socket that connects to the console. I took a q-tip and some alcohol and cleaned it out and it works great. I have a third party controller that does the same thing as the one you have. I didn't want to risk corrupt save files so I decided to stop using it.