O how I mourn thee, sweet trackball (with pics!)

[pragma]

Well, I tried it. I had a Logitech trackman marble (not the FX but the old-style one with a small ball) and I needed to take the optical ball mount off the circuit board if I wanted it to fit.

De-soldering was not as easy as just cutting the spider-like pins and connecting them with 22-gauge wire. When I soldered the wire to both ends of the freshly cut pin, and rebooted my computer, unfortunately now the trackball does nothing. Nothing at all. Nada. The buttons still work.

I've reviewed my work time and time again, checking for contacts or shorts, but I've found none. I guess this just isn't supposed to be done this way.

Super high-res shots at http://gallery.vandewolfshaar.com/Butchered_trackball/

For those of you who would like to see the poor, butchered trackball guts:

[RubbrDug]

Doesn't look too bad, even when looking at the first picture my first idea was, that you soldered the pcb to a dead mouse .

This is just guessing, but if you overheated nothing you should check the polarity of the black cables.

RubbrDug

[brandon]

Doesn't look too bad, even when looking at the first picture my first idea was, that you soldered the pcb to a dead mouse .

This is just guessing, but if you overheated nothing you should check the polarity of the black cables.

RubbrDug

Yeah I would agree about the heat thing.. certain things are very sensitive to heat so that could be it.. One other thing you could try is using an ohm meter to see if anything is shorted together and also whether of not those wires are broken.. its not likely I guess, but you never know.. I've banged my head against the wall lots of time only to finally find a broken wire

[pragma]

Hi Brandon, RubbrDug, all,

Here's what I did with the black wires and why they appear reversed. The black ball mount originally sat on top of the circuit board right over the hole that looks like a keyhole. The double wires on either side of the centre four-wire cluster were coming from two LED-like things (probably actually are LEDs to illuminate the underside of the ball). Unfortunately, the wires were leading down, away from the mount, which is not where I wanted them. Instead, I oriented them 180 degrees, with the wires now pointing upwards (see pic).

So, when connecting them back to the circuit board, I reversed the wires... i.e., the left mount pin leading to the corresponding right pin on the cb, the right mount pin leading to the corresponding left pin on the cb, and same for the other side of course.

I imagine I can get an ohm-meter at Radio Shack. Can anyone explain how I would use one to test out these circuits? Also, is that the same as "checking the polarity"? If not, can someone teach me what tool to do that with and how to use it too? :-)

Thanks
Paul

[Beley]

If i understand what you are saying about the black wires, i think you wired them backwards.  

you didnt need to reverse the wires since you only bent the led legs to face upwards they still should be connected the the same pin on the board.

Also from looking at the super high resolution pics i can tell that the left (looking at the ball mount from above) led is indeed wired wrong(assuming the "+" on the board represents positive), I cant see the other led well enaugh to tell for shure if it is also wired wrong

If you look closly at the led you can see that one side if flattened, this usally indicats that it is the negative terminal (ie leg/wire), also if you look clsly at the metal bits inside the led you can see that one of the 2 pieces is bigger then the other, the big piece is also usally connected to the negative terminal.

By carfully following the wires comming from the led it looks like the one attatched to the negative side of the led is going to the pin on the board with the "+" mark.

So if you switch both sets of black wires around (assuming you wired other led wrong also) it sould work.

Also, the leds apear to be wired in series, which means if you make a mistake on one of the leds(wired backwars of bad connection) the other led will also not work (just like xmas lights)

[pragma]

Great info and advice, Beley! Thanks!

I want to correct a possible misunderstanding. I didn't just bend the pins upward. I rotated the LED 180 degrees. That means, at least in my mental model I'm referring to right now (the actual part is at home!), that for each two-pin LED, what used to be the left pin is now the right pin and vice-versa.

I will double and triple check this tonight, and get back to you. If there are more pics you would want to see to help out, just ask.

Thanks again
Paul

[pragma]

Another thought - if it is the LED, I should be able to confirm by seeing if I can get the mouse pointer to "wiggle" at all by letting natural light in and kind of jiggling the ball over the optical receiver. If I can confirm it's an LED problem, I'm part-way to the solution.

Paul

[Chris]

Am I missing something?  Shouldn't it be easy to see if the LED is lighting up or not?

[Beley]

.....I rotated the LED 180 degrees. That means, at least in my mental model I'm referring to right now (the actual part is at home!), that for each two-pin LED, what used to be the left pin is now the right pin and vice-versa....

ah, ok if you rotated the led then mabey you did wire it right, in that case it might be a bad solder connection

...if it is the LED, I should be able to confirm by seeing if I can get the mouse pointer to "wiggle" at all by letting natural light in and kind of jiggling the ball over the optical receiver...

That might work, also what might work is to pull one of the leds out and fire a remote control through the hole and try to make it wiggle, as a remote control uses IR ligh also

Am I missing something?  Shouldn't it be easy to see if the LED is lighting up or not?

The leds are IR (InfraRed) leds, you can tell because they often have that blue tint in the lens.  However depeding on the led and how good your eyes are you can sometimes see a dim red glow when a IR led is turned on in a dark room

I should also mention that the ways of telling the positive and negative leads on a led that i described in my last post(ie flat side, big/small metal bits) are not allways correct, i have run across a few led that dont follow these rules but they rare , i would guess only about 1-5% of leds

[pragma]

Yes, I should think so, but it's inserted pretty deep into a well and I never could (even before dismantling it) see any light from the darkened "window" where the optical pickup lies. For all I know, these LEDS could be emitting in a non-visible spectrum also.

Paul

[pragma]

OK, I rewired it the other way, against my better judgment but in line with the flat terminal being the negative and... the whole thing is no longer recognized as a mouse. Oh well. Time to rewire it the other way again, recheck everything one last time, and maybe, just maybe give up. Unless somebody has any other troubleshooting ideas of course! :-)

Thanks for all the help
Paul

[pragma]

I got it working! :-)

Beley, your instructions were 100% correct. The flat side going to the negative terminal on the board (or rather, the one not marked +) was the config that eventually did work. I basically unwired everything and rewired everything (my soldering skill improved significantly by the end, and so I thought it might make sense the make them all the quality of my last one.)

And... lo and behold... I even have a button wired in now.

Thanks for all of your help. I guess I mourned too soon!

Paul

[Beley]

Just glad i could help

[BeBoxer]

A quick tip I learned for debugging IR LED stuff. Most CCD's are sensitive to IR, and it'll show up in the images. Since you have a digital camera, you should be able to see if the LEDs are illuminated in the viewfinder. You might have to be in a fairly dark room for it to work. I took this with my Canon Elph. I can see the IR LED on my optical mouse in the viewfinder, but couldn't get a good picture of it.

On a related note, the CCD's I've tried don't seem to be sensitive to the 1310nm light used by fiber networking. Or at least the amount of light isn't visible. Oh well. But that's way off topic.

[pragma]

That is a great tip, BeBoxer. Thanks!

Paul