HP 1331A X-Y display blanking

[Jules Richardson]

Has anyone got a manual for an HP 1331A X-Y display? It's a storage-tube 
device, and I'm curious to know if there's a way of triggering the erase 
function remotely rather than having to physically prod the erase button on 
the front.

The rear just has X-Y-Z inputs, and I *think* that X-Y are supposed to be 
in the order of +/- 1V, while Z is the intensity with 0V being full and 
around 1V being off. Maybe throwing a negative voltage at Z erases, or 
something, though.

cheers

Jules