Accidentally connected Tectronix TAS475 probe ground to 120VAC and it's ...fine?

Discussion in 'General Electronics Chat' started by Metatronic Mods, Sep 9, 2016.

  1. Metatronic Mods

    Thread Starter New Member

    Aug 17, 2016
    So I accidentally momentarily touched my probe ground clip to the + output of a full wave rectifier, probably sending some ungodly amount of current through the scope's ground connection, however briefly. So after removing the hazard, I go to asses the damage to scope and probe, and notice the scope's CRT display is oscillating, like the beam is at every point being summed with a (60Hz?) sinusoid.

    I turned the scope off, waited a while, and when I powered it back on, the oscillations are gone. I try the probe with a known signal source and everything looks good on the display.

    Does anyone know what would cause this? It seems like whatever ground fault protection the TAS475 has caused the ground impedance to increase for a short while (causing the scope output to "float") or is it just an effect of wires heating up causing higher resistance in the ground return?