[Test-Equipment] HP 141T spectrum analyzer question

[John Miles]

Is there a line-trigger or line-sweep option on the 141T?  If so, try
enabling it.  If the bumps stop 'walking', then you've got 60/120 Hz leakage
in a power supply bus somewhere.  As John says, it's probably a filter
capacitor whose capacitance has gone down or ESR gone up with age.

-- jm


> greg mijal wrote:
>
> > However,  the straight line trace at the bottom of the screen
> is no longer
> > flat.  It has a series of bumps in it and they walk accross the
> screen while
> > the analyzer is scanning. ..........
>
> Try varying the sweep time and see if the bumps move at a
> differrent rate. It
> smells like a filter cap that has dried out, has reduced capacity, and is
> causing ripple on a power supply to me.
>
>