On Friday, April 21, 2017 at 11:37:24 PM UTC-7, wrote:
I'm looking at a repair manual for a high powered transistorized audio
amplifier. It repeatedly says:

DO NOT use any test equipment to test or evaluate this amplifier, which
does not have floating grounds.

Possibly it means that the 'ground' terminals are actually connected to the
AC neutral wire (not to a third-wire ground). That connection is
permitted only with limiting resistance so that shock hazard is nil,
but 'test equipment' can easily see high-voltage transients.

That would make sense only if this is a two-wire AC powered gizmo.
It would make MORE sense if the device were an old TV set.