Testing card reader motor for 65

[Michae Altmann]

The card reader in my HP 65 isn't responding at all. I removed the back and unsoldered the wires attached to the card reader motor. Then I used jumper wires to bring 3.5V to the motor, positive where there was a red wire. I get no response. That seems indicative of a burned out motor. Right? Or is there some way that it jams up? The rubber wheel will also need replacing, but it doesn't seem worth taking everything apart if the motor is dead.

[John Robinson]

It does sound like the motor is bad. Does the shaft move smoothly when you manually give it a spin ?

Cheers,
john

[Randy]

Does it draw any current? A no load motor (removed from calculator) should draw 5-10 ma. If there is no current draw, twist the shaft with voltage applied and see if it will start to run. Many times an older motor that has been exposed to corrosion or a nasty environment will have dirty armature contact and manual rotation of the shaft may be all it needs to make brush contact and run.