wiggly, unstable measurement signal

[andia]

I have a 500 series module for repair that exhibits a "wiggly" measurement response. I send 1kHz through it. as long as it is in bypass the response is stable, when I engage the processor the scope in my analyzer shows an instable response as if a lower frequency is overlayed somehow. it is also visible in level variing and frequency count. what is causing such behaviour?

 

[gyraf]

set your scope so you can analyze what is actually going on? From what you describe, it could be the trigger in your scope that's unstable..?