On Thu, 14 Feb 2019 13:47:40 -0600, Fox's Mercantile
wrote:

On 2/14/19 1:25 PM, wrote:
The Chinese probes only have a model number-P6100

That alleges they are clones of the Tek P6100

So, as near as I can tell, the probes are all right,
at least they all act the same. But what causes the
distorted square wave at the 1x setting?

All scopes have a basic input impedance. For a 1:1
probe to "look right" the probe has to match that.
Mostly it's a matter of the scopes input stage being
properly compensated for the probe's cable.
Can this basic input impedence be adjusted? Should it be?
Eric