On Wed, Sep 03, 2025 at 05:18:44PM +0100, Rob Jarratt wrote: > > > > -----Original Message----- > > From: Jon Elson via cctalk <[email protected]> > > Sent: 03 September 2025 15:39 > > To: [email protected] > > Cc: Jon Elson <[email protected]> > > Subject: [cctalk] Re: Repairing an Olivetti M24 PSU > > > > > Those are not real. They are conducted interference from the switching > > supply getting into the scope preamp via the ground lead. > > > > I have seen this MANY times, ignore it. > > > > Jon > > Thanks Jon, obviously I don't have enough experience to know this. How can I > recognise this in the future? >
One test I do is put the probe and ground clip both on ground. If you still get a good amount of noise you know its not real. Works best when ground and where you are probing are close together so you aren't moving probe much to do the test.
