123tim said:Mark,
Thanks.
I was thinking that the brown components (Caps) were glass diodes with black cathode markings on the ends. I thought the black components (diodes - I assume) were surface mount resistors. This is pretty cool. I think that a new type of forum could be started where a circuit is identified and diagnosed from a picture!
Thanks for the clarification. Thanks for explaining the 22 KHZ tone too. I can see that now.
It looks like your first thought was correct and mine was not. What I called caps look like cylindrical diodes possibly Zeners?? . I still think that given the topology the six small black components are pin diodes.
With this excellent picture one could easily reverse engineer it even without seeing the other side of the circuit board.