Laptop touchpad response badly when on power supply?

Recently, I discovered touchpad malfunction (i.e. jumping, erratic, etc) in two of my laptops due to a power adapter. I checked the voltage with a multimeter, and it was in range. Also, I did the RF interference test explained in other posts, and found no interference caused by the power adapter.

Finally, I followed the pevious post to eliminate the capacitance charge touching the ground metal of the labtop, and the touchpad control improved a little. So I desided to have a better ground connection somewhere outside the laptop. I used a piece of thicker aluminum foil from a sealer of a ground coffe container. Then I managed to open one of the plastic covers at the bottom of the labtop, and secure the aluminum sheet with one screw inside the cover. Then I bend the aluminum sheet to have an exposed sueface outside. Finally, I secured the edges with etectric tape. This creates a permanent grouding surface that can be touched by hand or my lap.

I tested and it works great. The adapter does not afect the touchpad anymore. Just make sure the aluminum sheet only touches ground and no any other circutry connection.

Sometimes in windows when you plug the power in, it changes the battery/perfomance mode to MINIMAL PORTABLE/LAPTOP, check that it does not do that.

In Control Panel double click Power Options. Here you can set timeouts for your monitor, system standby, and hibernate. Notebook computer users can specify an alternative power scheme that will take effect when the PC is running on battery power.

Another problem can be the system driver, make sure you have the original HP driver installed.. Usually the mouse pad from HP use the Synaptics Drivers, and that should reflect in the device manager.

If the problem persists it is most likely going to be hardware related, by the sounds of things this is an old notebook, and could just have some fault components.. Sorry.

I have the same problem on a Sony Vaio VGN-FZ140E that I bought in June 2007. The touchpad was intermittently becoming very non-responsive and could barely track my finger. After reading the above posts, I realized that I too had recently replaced the power adapter with a cheapo ($10) one from Amazon. I unplugged it and - presto - no more touchpad problems. The adapter I got works fine in charging the battery, but I did notice that per the specifications written on the brick, it puts out about .8 more amps than the original. I don't know if that has anything to do with the problem, but it was something that caught my eye because the Amazon page said it was a replacement for my exact laptop model. I did some further testing to see why the problem was intermittent for me. It turns out that when I plug the new adapter into a short, ungrounded extension cord that I occasionally use, the touchpad problem goes away.