Does not work

, actually I'm not able to making it work, so I'm angry with myself, I've done the spinner hack before and was a piece of cake, so i taught that this thing was the same.
I tried the hack with a cheap mouse (the us PCB is too big) but seems that is not working checked with a multimeter on and i always get -5 volts instead of +5 (i didn't misconnected the probes) plus the central pin of the optic receptors of the mouse does not output any readings (thevoltage remains 0) while the external pints give -5 any suggestion? Forgot to mention that the buttonworks fine.
I forgot, does some1 know a way to test the optics of the trackball (in case I've burned them) i don't have access to a c64 or an Atari to do a Field test.