Thinkpads Forum

I am using a T60 that's about a week old. Despite being new, I have noticed that when using the ultranav pointer, often when I take my finger off of the pointer it drifts slowly upwards a short ways. It only does this sometimes, but at least once every few minutes with normal use, and it's already annoying.

Is anyone else experiencing this, and is there anything I can do to correct this?

thanks,
jonathan

I have exactly the same problem as you.
It's really annoying.... I called service, they only helped me upgrad the drive revision.
But the driftting remains....
Any one can help ??

I believe that this is the pointer recalibrating itself. Sometimes it takes a little while, this happens on my 600X also. Although...once every few minutes does seem very very drastic.

nick-m wrote:I believe that this is the pointer recalibrating itself. Sometimes it takes a little while, this happens on my 600X also. Although...once every few minutes does seem very very drastic.

I would think that re-calibration would be a separate process, which is what I was wondering about.

Any other input on this?

if you tend to "lean" on the trackpoint, when you remove the pressure the cursor will drift the opposite way that you had pressure applied..
it will recalibrate itself almost immediately..
usually within an inch or two of free movement..

you will usually KNOW when the trackpoint packs it in..
it will stay at one edge and not move off that edge..
or it won't respond at all..

THAT is when you call and they'll send you a new keyboard complete with the trackpoint..
its a customer replaceable part..

I have had pointer drift with every one of my ThinkPads - TP600, T21, T42. Just got a T60 and did not notice it yet but I wouldn't be surprised. When that happens, I learned to just let it go. It will stop on its own. It seems to need to do that to recalibrate, maybe to compensate as the machine heats up.

This also has happened on every one of my thinkpads. It also has happened on all my dell's with trackpoints. Ive always just thought it normal.

BillMorrow wrote:if you tend to "lean" on the trackpoint, when you remove the pressure the cursor will drift the opposite way that you had pressure applied..
it will recalibrate itself almost immediately..
usually within an inch or two of free movement..

you will usually KNOW when the trackpoint packs it in..
it will stay at one edge and not move off that edge..
or it won't respond at all..

THAT is when you call and they'll send you a new keyboard complete with the trackpoint..
its a customer replaceable part..

Sounds good. I definately don't lean on it too hard, but it's nice to know that it's recalibrating itself.

Setting it to a lighter activation force (higher sensitivity) has usually reduced the recurrence of this in my history of T'Pads, but I've experienced it with every Trackpoint type device that I've ever used, regardless of make.

It also extends the life of the "eraserheads".

YMMV

Scratch wrote:Setting it to a lighter activation force (higher sensitivity) has usually reduced the recurrence of this in my history of T'Pads, but I've experienced it with every Trackpoint type device that I've ever used, regardless of make.

It also extends the life of the "eraserheads".

YMMV

What do you mean it extends the life of the eraserheads? How so?

Yes indeed the drifting is completely normal. No matter how you use the track point it will, from time to time, recalibrate itself. It's preferable to take your finger off and simply wait until it's done drifting as it's recalibrating. Then you may resume using the trackpoint.

Cheers...

I was just saying that the RED trackpoint heads seem to last me a little longer when I set the trackpoint to a lighter activation force. It makes some sense as you're not "crushing" them to get the pointer movement.

Thats normal i had the same issue before with my R40 R51 Z60 and now my T60

It is simply the recalibration to adjust the proper gain for negative feedback. If you tend to place a large load on the edge for any extended period of time, it will recalibrate to maintain its response range and account for that load. Once you take the load, i.e. a finger, off, it will start to recalibrate to center position again and re-adjust for a new value for the proper negative inertia, causing the movement.

Some articles on the Trackpoint;

Negative Inertia Implementation Overview

More about it and some background and comparisions; in this, note how similar the joystick trackpoint mouse is to the Apple MightyMouse today

R&D Engineering Article on the Negative Inertia Algorithm including transfer function graph and impulse response of the negative inertia filter, which is a form of PD+ Control by the way in combination with a special trackpoint circuit to counter any additional noise added by the derivative control. Derivative control, PD or AD, gets noisier the more you do it, but is faster in general, and PI, integrational, control reduces noise and tweens response but takes longer to reach steady state. I would post the link to the trackpoint circuit paper on the Almaden IBM Research site, but it has apparently disappeared since I checked it last.

Next, the Amazing and Rare Two Handed Trackpoint!

As well as the Tactile Trackpoint!

Getting carried away with this; also of great note are the Science Exploration Wand and the aforementioned Trackpoint Mouse.

That should do for now; HTH

Sorry in reopening this thread... but I was looking for a solution because my trackpoint drifts in different directions quite often after use.

I was trying to find a solution and discovered that when it did start drifting and wouldn't stop I proceeded to take the red thinkpad pointer off and it would stop. After finding out that it is the trackpoint itself which causes the "joystick" under the red cap to move the cursor even after I take my finger off it. It is probably due to little bit more pressure that I put on the trackpoint.

So I changed the trackpoint that was originally on the keyboard and put a cat tongue trackpoint. Since it is smaller that the original red cap put on thinkpads nowadays, there is definitely less drifting.

I guess what I was wondering was whether other people who have this problem found a definite solution.

I believe one the reason for the cursor to keep moving by itself is because the base of the red trackpoint sometimes get impacted to the bottom of the joystick in the keboard causing it to move.

A solution that I believe is to file down the height of the red cap at its base so that it doesn't touch the base of the keyboard. But the problem with that is that the red cap doesn't stay on the keyboard. Perhaps cut the trackpoint in half and superglue it to the joystick part?

I guess I am writing this post to see whether there is a better fix rather than the superglue... and for those who say use less pressure on the trackpoint - I do but still there are occurences of drifting at times...

I would definitely advise against going the superglue route. But good pointer about having the bottom of it touching anything, although this should not happen in a properly assembled keyboard unless there is a foreign body somewhere.

When it happens I just let it go and wait for it to settle; small price to pay for the convenience.

Thanks ... I didn't do the superglue thingamajig. After some thought I placed a very small piece of tissue inside the bottom of the red cap and put the cap back on the keyboard, thus creating a little space between it and the keyboard. It worked and no more drifting ^^

With this solution, I am beginning to think that maybe as claudeo wrote it is a manufacturer defect in that the height of the keyboard portion of the trackpoint is not high enough to compensate for the red cap from touching the base of the trackpoint. Hopefully someone at Lenovo takes note.

Oh well... I admit the trackpoint is ever slightly mushy but after using it a bit I like it and most importantly it sure beats drifting.

For those who will try this method I suggest that if the cap is too loose, don't throw away this method but put less tissue in it ^^ and also to make sure that the tissue is packed all the way to the bottom in a thin layer... (if it drifts a bit put a little more tissue etc...) then again there is always the Superglue route ^^

I want to add that with the "added" little space between the base of the red cap and the base portion of the keyboard there is less likely and need for the computer to recalibrate itself because there should be no mislignment of the joystick portion of the keyboard after each use.