Inconsistent readings on Analog Ports

Hi everyone,

I'm having a little bit of trouble trying to get simple readings from A0 - A5 ports.

I'm using the code for AnalogueReadSerial just as it comes from the example sketches menu.
The thing is, no matters how much I turn the pot either to the right or to the left the reading on the monitor shows me a fluctuant value around 300 or 400.

I've double-checked the connections. (middle pint to A'x', outer pins one to 5V the other one to GND)

I've tried using each analogue port and the reading is mostly the same regardless having the pot assigned to it or not.

Then I proved changing the breadboard, and using several pots (10K, 50K and 100K Ohms)

After that I thought then I could be the chip so I tried on two different arduinos and nothing changed

Now I'm worried it could be the machine!!!

Any idea or previous experiences of any o you guys that could bring some light over the issue???

PD. I'm running an R3 UNO in an OSX 10.7 machine

Have you measured the voltage at the analog input with the pot connected to be sure that the pot is wired right and functioning?

Sounds like a wiring problem, not your PC at fault. I'd have a close look to check your breadboard doesn't have gaps in the rails which need to be bridged. Take a photo of your set-up and let us have a look.