Having a jittery touchpad

This is really annoying.

My laptop's power adapter is on the fritz. It started getting flaky a few days ago, but I put off buying a new one.

What can I say? I'm trying to watch my expenses.

Unfortunately, it's very nearly dead right now. Its connector is flaky, and due to the molded cable, I don't think that simply fixing the connector will be entirely feasible.

I did have a universal laptop power supply lying around from a previous project. It lets the user select an output voltage and one of several barrel-type connectors. Unfortunately, it has this odd effect on my touchpad. It makes the touchpad kinda jittery.

I suspect that the power supply doesn't regulate its output very well. That's darned annoying.