Have a look at the attached pic of the back (solid copper side). You will see 2 holes which are plated through to the other side (the copper tracks side). If you look closely at the holes you will see they are electrically isolated from the solid copper - that's how it should be. If your board has no such isolation then the tracks are being shorted to the solid copper side. To remedy that, just drill through the holes to remove the through hole plating. Make sure you solder your wires on the track side of the board. Also check the 4 corners of the board where the screws and springs go - there should be similar isolation there too.
↧