Small signal on an OWON SDS-E

[gildasd]

Hello,

I used an Owon SDS-E today, and found that one of my circuits has an annoying "quirk":
A 555 timer causes a regular "spike" when it "switches".
It's about +20mV and -20mV.
I think it's every 30uS.
On the 30MhZ scope, even captured at max resolution, the spike is never more than a single pixel wide for both up and down.
This should not be problem, but it "leaks" into my opamps via the -Vcc...
And is spread out to creates a nice "heart beat" at the same exact frequency.
Sorry for the lack of screen capture, I had to vacate the class before I could...

What could be it's duration so could calculate a filter via C*R=T if not to remove this, at least tone it down?

And the real question, my personal Philips scope (15Mhz analogue), the school's Tectronics (20Mhz digital) both failed to see the original signal and let me trace it down.
so in basic scopes, which one could "see" this well enough to be able to work on it?
It won't be a Owon because it's low voltage measurements are not good for my use:
For example, it was steadfast indicating 32mV on a signal that two 175's, a UNI-T61, and two Tectronic scopes were indicating as 9mV...
Changing channels and using 4 different probes all gave me the same results.