Dell M4800 - Track Point Not Working?

MJS,

Basically, M4600's cable does not work on M4800 and M4800's cable does not work on M4600.

When I hooked up M4800 keyboard into M4600 using M4800 cable, ENTIRE keyboard does not work. No backlighting, literally not a single pressed key would work. As if keyboard does not exist. And you were right. When keyboard does not work, the 3 buttons dedicated for trackpoint also does not work! (Disabled automatically!)

But the fact that M4600's ribbon cable also does not work with M4800 (and vice versa), I feel like it really is not M4800's keyboard. Physically they look the same with same number of pins, But I have no idea why they are not compatible with one another.

Currently I don't have tools to test electronically. But I REALLY don't think it's the physical aspect of the cable damaged.

Keep the ideas coming please haha I will keep trying. Im sure this thread will be useful for someone down the road. Literally not a single person has had in the history of Dell (That I can find online) with trackpoint physically not working.

 

I’m afraid I’m out of ideas here.

The new BIOS contains a newer version of ‘embedded controller’, whatever that is, but your problem really seems hardware-related. And now that I’ve tried myself what disconnecting the coin-cell battery does to a computer, I doubt there is any ‘harder’ reset normally available.

Also, I have noticed a simple setting in BIOS where you can disable the touchpad (by selecting serial mouse, I suppose), and you might then re-enable it, but do we really believe that this would help?

I haven’t seen and touched the ribbon cable myself but it’s still a folding cable, and, as such, the most likely point of failure if the system has been reassembled. You know, the cable could have had a hidden defect which you just made show with its unfolding and refolding.

You just need to borrow a ‘continuity tester’. If you know anyone who repairs stuff as his job, or on a regular basis as his hobby…
The only other implicated part is the motherboard. There isn’t really much room left for other lines of thought in this case.

BTW, I have noticed in the Owner’s manual, among the things to do before ‘working in a computer’, that one should ‘ground the motherboard’ before going in. That’s done by pressing the power button after the main battery has been taken out. I’ve no idea how high the risk is to damage anything if you forget, or whether you know to do this.

 

MJS,

I ground the board and all the goodies before starting. I found a friend and dragged him home so I can test out the ribbon cable haha. Yea my cable works perfectly fine in his, including trackpoint and all.

Looks like the only theoretical possibility is the motherboard...

After that hard CMOS battery reset did nothing..

I feel like a chip that regulates trackpoint itself must have gone bad somehow. This is very strange after all.