Commodore 1520 Plotter

They're the same pens as for many other 'plotters' -- like the Radio Shack CGP115, Sharp CE150, etc. If anyone knows of a current source [1] I've got several of the machines... [1] I do not want to start a thread about op-amp + transistor + sense resistor circuits ... Actually, somebody should maintain a list of compnanies that still sell consumables for classic machines -- printer ribbons, thermal paper, plotter pens, etc. The main thing that fails in these plotters is the motor pinion. It is pushed onto the stepper motor spindle (1 for each axis) and it splits. When this happens, of course, it slips on the spindle and no longer meshes amoothly with the next gear. The Alps service manual for the mechanism doesn't list the pinion as a separate part (you are supposed to replace the motor), but I have heard htat Radio Shack used to sell thme as spares, Of course not any more... If the pens arestill available, I might be more willing to try to find or make a replacement pinion... -tony