i have a plotter! i can finally be part of #plottertwitter !
Panasonic Penwriter P400C, uses ALPS DPG-1302 plotter mechanism. keyboard needs repairs, original pens mostly dried up but the green still works! has RS-232 built-in so can be controlled from modern devices thru serial
so i left the ballpoint tips soaking in alcohol overnight because there's still ink in the pen bodies (my stained paws are proof) but it wasn't getting up to the ballpoint tips. unfortunately not only did this not work, i ended up mechanically breaking the tip for my black pen...
... such that the ballpoint dislodged itself into the pen tip. so considering i can't recover the original pens, i ordered some 0.7mm ballpoints & i'm going to try to devise a way to make them into brand new no-old-parts plotter pens through some 3d printing. digits crossed!