Full BW switch and labelling on volts/div on 7A26

Benoit Robert <robertb3@...>

Hello Tektronix gurus...

A couple of questions here:
I own a 7903 frame with a 7A26 vertical amplifier and 7B92 time base.
The traces are nice and super sharp with the BW limited to 20 MHz.
When I go to full BW, two things happen: the traces gets a little
fuzzy (about 3 times the thickness of the previous traces) and
they jump up about one half of a minor division. Now, I understand
that bandwidth has gone up 10 times and naturally, some noise finds
it way though the amplifier so this is normal to a certain extent
but I was surprised to see this amount (even with the coupling switch
set to GND). Brightness is set correctly and so is the focus.
I was wondering how much is typical of the 7A26 plug in ?

Second question (this one is easy):
The 10 mV mark on each channel is marked in reverse (white on black).
What am I missing here - What is the reason behind this ?

I find my unit quite nice (but it does take some getting used to -
coming from a THS720 digital scope here).
I can't believe all the nice features in this unit though.
I bought this scope used a couple of months ago mainly to
look at RF signals in the VHF/UHF region.

Thanks in advance,
Benoit Robert

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