I came across an interesting problem tonight and thought I would share it.
I was working on Ajax, (robot #1) and decided to use the PLAY command in PICAXE BASIC to make him "sing".
It looked really easy to use, preloaded tunes, give it the pin for the piezo speaker and the number of the tune and it should work.
And it did kind of work. I worked on EVERY output pin but the one I had the piezo speaker connected to.
I had the piezo speaker on output pin 3 and got ...nothing....
But if I used pin 0, 1, 2, 4, 5, 6, or 7 I could hear the tune, of course the servos and motors all connected to these pins twitched, ran, or were generally unhappy.
I finally looked at the board and realized I had plugged the piezo speaker into V+ and ground but NOT data for pin 3....uh duh....
Once I moved the wire from V+ to data, everything worked.
The symptoms of this bug were so unique I thought I would pass it along.