HP97 The journey begins

[teenix]

Hi all,

The modification did not make any difference to the printer drive.

Attached is an image showing the different print line widths. The paper is crooked, not the lines. The line spacing is uneven because the old rollers are not gripping the paper properly.

You can also see the effect of the software controlled print intensity adjust.

It would seem that I will have to recreate the original motor driver setup, although it would probably be better and more compact with a newer H-Bridge device. The trouble at the moment is, that the semi-conductor shortage is having large delays in delivery for some of these items.

The motor chip that I am using has direct PWM input so I can try driving it directly from the PIC and then try and add the closed loop control as per the original circuit. Somewhat of a chore with tiny parts.

cheers

Tony