From: Jim Strickland <jim_at_calico.litterbox.com>
>So I'm a 'scope newbie, does the probe impedance (13 pf) have to match the
>rating on the jack on the scope (47 pf) for the waves coming out of the
>calibration jack to be properly square? And if so, does anyone have a source
>for probes that work with ancient scopes like this?
>
Most probes can be adjusted to work with a range of capacitance, they
normally have a little adjustment hole at the end that attaches to the
scope. Adjust it for the flattest trace.
>Also, how do I tell a 535a from a 545a?
>
Look above the CRT and see if it says TYPE 535 or TYPE 545? I assume
this is a big old tube scope, if not ignore the rest.
>From Oscilloscopes, Selecting and Restoring a Classic by Stan Griffiths
the 535A is 15MHz bandpass 5MHz trigger. 545A 33 MHz bandpass 5 MHz trigger.
Bandpass may be less depending on what plugin is installed.
I have a 547 (50 MHz bandpass and trigger) which I use to maintain my
PDP-8's. Mine is a nice scopes but can be a little temperamental.
Depending on what you are using it for the limited bandwidth (especially
trigger) may be an issue.
David Gesswein
http://www.pdp8.net/ -- Run an old computer with blinkenlights
Received on Sun May 06 2001 - 11:23:23 BST