It's time to restore the 11/45.

[Roe Peterson]

On Feb 5, 2015, at 2:17 PM, tony duell <ard at p850ug1.demon.co.uk> wrote:

>> 
>> Ah. That's the part I was missing! I (naively :-) assumed that the 'scope's
>> whole input amplifier would be 'floating', and the input signal would be taken
>> as referenced to the 'ground' on the probe, which could itself be floating.
>> 
>> Clearly not! (I'll have to look at the manuals/prints for my 'scopes -
>> Tektronix 465's - to see if they are this way. Anyone happen to know,
>> offhand?) Thanks!
> 
> I am darn sure the Tekky 465 does have the 'ground' of the input amplifier --
> the outer of the BNC probe connector -- tied to mains ground (and the metal
> chassis/case of the instrument).

Absolutely correct.