Re: 7904A checkout + calibration


 

On Mon, Jun 1, 2020 at 06:35 PM, Eric wrote:


What you need will vary greatly based on the plugins you need calibrated.
... and on your requirements for the performance and calibration of the mainframe.

If you are going to use your 'scope with the same horiontal and vertical plugins all of the time and at relatively low edge speeds (lower frequency, longer rise/fall times, your requirements will be modest.
If you intend to use the mainframe with higher requirements and/or several different plugins however, some sort of standardization/normalization is required, especially as regards vertical amp behavior.
The best way to achieve a normalized mainframe would be the use of at least one, preferably two 067-0587- 01 or even one -02 Calibration Fixture/Signal Standardizer. Unfortunately, these are difficult to find and expensive. The -02 would only be really needed for the vertical system (edge speed) of a 7104.
Most importantly, these normalizers allow you to check and adjust the step response (high frequency behavior) of the horizontal and vertical system, avoiding the influence of any (non-calibrated) plugin, and the mainframe's horizontal and vertical sensitivity, linearity and distortion.

A traditional and still very convenient calibration set would further include a TG501 Time Mark Generator, which produces calibrated marks (needles) for time base plug-in adjustment, a PG506 for vertical amp amplitude sensitivity, LF behavior and plug-in step response adjustment (up to about 2ns edge speed).
A sine wave generator (like an SG503) would be nice for trigger-offset and -sensitivity adjustment.

Very nice and convenient all but you'll definitely exceed what you pay for the 7904A with this lineup. Any one of the instruments would be useful, especially the PG506.

Official calibration documents state different requirements.

Raymond

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