PDP 11/24 - A Step Backwards

[Jon Elson]

On 3/28/22 21:55, Jon Elson wrote:
> On 3/28/22 17:22, Rob Jarratt via cctalk wrote:
>> Its 600mV, but it is more of a spike than a ripple.
>>
> That's probably not real.  It looks like noise pickup from 
> the probe ground lead.  Try disconnecting the probe tip 
> and see if you still get similar signals.  I have seen 
> similar noise lots of times when measuring things with 
> switching power supplies.  The high frequency content is 
> pretty unlikely to be actually there on the power rails, 
> with a bunch of decoupling caps all over the boards.
>
> Jon
>