Black Jupiter 2000 Function generator circuit.

[Skywave]

When you've got a piece of test kit like this and it isn't working the way you describe and the cct. diag. isn't available, the best chance you have of diagnosing the trouble is first to get the data sheets for all the int. ccts. that are used and wander around the cct. with a 'scope, paying particular attention to waveform shape and amplitude at the various int. cct. pins, using the datasheets as a guide. It's also a good idea to check that the supply voltages at the appropriate pins of the int. ccts. are present: in fact, this should be done first!

Al.