Re: SUCCESS! The "sick" 475A is now the "fixed" 475A!


On Wed, Dec 9, 2020 at 02:38 AM, Harvey White wrote:

All the other waveforms are specified to amplitude (IIRC) and *not* risetime.
That is correct. Two notes:

- The PG506 used to contain low-pass filters on its amplitude-adjustment outputs, except for the highest amplitudes. This was to prevent internally generated noise to be visisble at low set voltages. The relays used to switch the filters tended to die, so in many units, the filters were skipped by moving the output coaxial cable (with Peltola connectors) from the filter output to the filter input. It was just long enough to do that.

- The high-voltage output was used to drive a separate tunnel-diode fast rise time generator for adjusting some faster 'scopes. ISTR that the tunnel-diode pulse had a rise time of about 100 - 150 ps.


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