intermittent buzz

[wellREDman]

I have a bass that has developed an electronic  buzz that goes away when I'm in contact with the strings, Ive had a look inside but cant see any obvious loose wires, its an active single pickup.
 any ideas what might be causing it?

[amptech]

A quick check could involve opening the cavity, and  move wires with something pointy whilst being connected to an amplifier.
This sometimes isolates the problem, if there is a loose connection or something. The wires to the jack is common, cut off 5mm or something and re solder. If still buzz, re solder all connections - checking the wires with a diode tester for continuety as well.

If it's still buzzing, you might have to check each component thoroughly.

Of course you have tried to replace/tested you instrument cable first..