Adjusting HP-97 card reader

[Ed Sowell]

In his great write-up on replacing the rubber drive wheel, Mike Davis says "Adjust slotted shaft until the card reads and writes properly."

What's being adjusted here? Perhaps the slotted shaft, which is the axle for the gear roller and gear, is slightly excentric so turning it moves the gear closer to or farther away from the worm on the motor shaft?

[Michael de Estrada]

Yes, the shaft is eccentric, but what is being moved is the rubber wheel against the card to increase are decrease the pressure. Too much pressure and the motor will strain and the card will pull through too slowly. Too little pressure and the card may slip and not pull through smoothly. The service manual uses the current draw in the motor as the card is held back in the reader to determine the proper adjustment.