Bonjour cher Monsieur
We have 576 and 577 for decades. ours were from local auction and Ham radio Fleas.
Typically shipping them is risky as the CRT and panel controls are easily damaged, sine they are heavy and bulky.
Few sellers are qualified to test fully or package safety for common carrier freight.
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All that aside, we found the lissijous type display needs a HV diff amp at the CRT V,H deflection plates.
Then a pair of ADC.
Still most digital devices and computer data acquisition cannot use the XY easily. Finally the scale factor fiber optic readouts cannot be easily acessed.
We avoided the problem by fashioning a CRT hood from an old scope camera adapter hood, then added a mask and support bracket for an iPhone. We setup the shot, place the iPhone on the mask, and set-up for a nin flash macro, perhaps 2x scale.
Result is all ambiance light is excluded, and a perfectly focused and centered image, with the iPhone coplanar to the CRT face.
Both scale factor and graticule lights are dimmed to setup the best compromise between them and the CRT traces.
We use the same technique on our 7104, 7904 as well as with 7K Spectrum Analyzer plug-ins on 7603.
Happy to send photos if of any interest.
Bon courage
Jon
Jean-Paul