HP 7550B Pen Plotter Operating W/Win 10 Help Plz

[Erik-M]

Do you have the HPIB/GPIB or centronics/RS232 version, the HPIB/GPIB version cannot be operated from the RS232 port.
The centronics one can be operated from the RS232 port, BUT did you set the dipswitches in the right order.

What exactly did you try and what went wrong.
What interface on the computer was used and was the interface properly configured.
Does the interface work with other peripherals (which ones).
From what software do you try to access the plotter, does the software talk HPGL in the right format.
Did you read the manual ? http://www.hpmuseum.net/collection_document.php

Most people here are technical (and old) enough to understand HP plotters but you have to provide a little more info.