Mysterious mouse problem

Ivan Seeking

Yesterday I was onsite doing computer work with a customer while sitting at a metal [stainless] table. Whenever the computer [my laptop] was on the table, my mouse pad was so glitchy that it was useless - the cursor didn't respond to most finger movements. We eliminated all potential sources of electrical noise but with no effect. If I lifted my computer off the table, the mouse operated properly. I tried sitting the computer on a piece of thick cardboard but even that didn't fix the problem.

I'm guessing this was somehow due to the damping of magnetic fields, but that is hard to believe.

Hobin

I don't know what laptop you use, but what *could* be the case is that the surface you place your laptop on causes a slight 'bump' in the case, which messes with your touchpad. On the other hand, I find this almost as hard to believe as a damping of magnetic fields, but it's easy enough to rule out: try holding and applying some pressure to the bottom of your laptop, and then see if it's glitchy again.

Other than that, I really have no idea. Have you tried different surfaces other than the table and the cardboard?

Ivan Seeking

Checking for torque on the body was a good thought, but nope. I can apply pressure to both side of the computer [including front to back] and still operate the mouse with no problem.

In my office I am normally working on a standard table surface and haven't had any problems. This was my first visit onsite [anywhere] with my new computer, so I may see more problems in the future. We did finally move the computer to another surface a few feet away and everything was fine again.

It is a Dell Precision... 4600... I think.

Sidebar: There was one job where my computer would fail every time I was onsite. As it turned out, the problem appeared to be altitude [I guess the ventilation was the real cultprit]. This was for a very small control room, about fifteen feet in diameter, located at least 25 feet [or more] underground... not sure now how far down it was any more. I had to climb down a vertical ladder from ground level. Someone back then mentioned that hard drives can be affected temporarily by pressure changes. So after that I went down and set up and then left for coffee. When I got back, my computer would boot properly again.

Ivan Seeking

You know, I'm wondering if this is a problem I've seen before. Perhaps local power is inducing currents in the table top. It is a long surface sitting against a wall.

I was remindeed of a problem I had many years ago where we had overhead power lines causing no end of problems on a mobile CAT scanner. I finally checked and could measure something like 130 to 140 volts AC to ground, on the body of the bus. When we looked up, there they were - big lines feeding the hospital.

sru2

It could also be a short in your laptop and the table is Earthing it. Use a multimeter.

rishi.sharma

Have you checked it with Charger/AC power cord plugged into the socket ?

Chronos

Sounds like some kind of loose connection to me. Mice are cheap. I've had the same kind of luck with keyboards and have gone through 3 in the last year or so. The last one got really weird on shift characters. New keyboard, problem solved [at least for now].

Lebombo

Happens to my laptop from time to time. I think its some sort of calibration issue. It always happens after I lift my laptop to carry from one room to the next or from one desk to the next. If I carry it with one hand, the touchpad will no longer operate correctly, even if I'm using one hand to hold it horizontally. I think that some sort of bending pressure I put on the hardware as I hold it with one hand messes up some sensors in or connected to the touchpad. This only happens when I carry the laptop when its on. And when this does occur, a simple reboot fixes the problem. It is a strange anomoly.

mishrashubham

Yes this would also be something that I would check. Does the problem occur only when it is plugged in? If yes, then there micht be a problem with the earthing. The capacitative touchpad won't respond well in such a case. Best solution would be getting a mouse or avoiding use while charging.