Re: 2445A calibration

Chuck Harris
 

Hi Maxim,

The normalizer is just a resistor and a trimmer capacitor
in parallel, but in series with the center conductors of
a male and a female BNC connector. It is built in a little
Pomona box.

You can do the same thing with a scope probe, using the
probe's trimmer capacitor to square up the waveform on
one channel, and the C205 to square it up on the other.

I doubt it needs adjustment, assuming that you haven't moved
it already.

That CAL03 throws a LIMIT on CH3 and 4 makes me even more
certain that your problem is your generator.

-Chuck Harris

maxim.vlasov@... wrote:

Chuck,

I read again the input capacitance adjustment procedure for CH1/CH2. I have no 15pF normalizer and the high voltage calibration generator.

I can observe that when 1 MOhm input on the scope is selected, the square waveform signal delivered by the BNC cable has a visible overshoot on the rising edge. So, likely the C105 & C205 have to be adjusted too. I wonder if this overshoot could potentially contribute to the CAL02 LIMIT problem on the channel 1 & 2.
However, when calibration CAL03 routing with other channels 3 & 4 the scope also throws the LIMIT error.

Thank you,

Maxim

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