Hi...

Made 30Mhz oscillator but could not see the signal on the scope (it was coming and going)

but realized if the probe is set to *10 : could then see the signal

*10 : so the actual signal is *10 of the amplitude displayed by the scope yeah?

"The attenuation circuitry results in higher resistance (generally a good thing) and lower capacitance, which is important for high-frequency measurements."
https://www.allaboutcircuits.com/technical-articles/an-introduction-to-oscilloscope-probes/

Please explain more : Thanks

 

When set to X1 the probe resistance and capacitance presents a greater load on the oscillator and, in this case, it seems that extra loading is enough to stop it oscillating. This is not an entirely unexpected result.