This is the proper HP test method to test the card transport operation (from the service manual with my additions):
Start by verifying the motor works. Unsolder both motor wires from the circuit board and apply 3 vdc to the motor (red is +).
With no card, the no load current should be no higher than 50 ma. A good, well centered screw will run quietly at less than 20 ma. Anything higher than 50 ma is cause for investigation, the usual cause is the lead screw is off center or is not seated fully on the motor shaft. If the unit squeals, a small drop of plastic safe oil on the lead screw socket will usually fix it. This can also be a bad sign of motor bearing noise which I will not address here.
Now, allow a card to feed partially into the reader and grab the card and hold it. Adjust the eccentric for approximately 200 ma with the card stalled. If you cannot get the current under 300 ma, there is a problem - usually the rings are too large. The normal position is for the dot on the eccentric to be at the twelve o'clock position with the card path being right to left.
Once you know the motor works and eccentric adjusted, re-attach the motor leads to the board. With power off, measure resistance between the common point (PC hole closed to the M test point) and the PC locations marked M F H. They should be > 10k ohm.
Manually push a card into the reader leaving 10 mm exposed. This will put the card in position to activate all three switches. Measure resistance again, this time each point should measure less than one ohm. Most likely, you M contact is not closing correctly which why your motor does not turn on.
If a switch is not closed, remove the circuit board and carefully clean the board contact areas and the leaf switch ends. Remove the card and re-insert, this time watching for the switch ends to move upward as the card contacts the balls and push the switch(es) up. Re-assemble and re-test.
If you *must* adjust the switches, understand how they work so you do not do any damage. Turning the adjustment screws clock-wise raises the switch end. Since they are all on one plate, they do interact with one another. Remove the board again and adjust all screws counter-clockwise until each screw just touches the plate. Re-attach board and re-insert the test card. Now, start with the M test point and adjust the screw closest to the M point clockwise until the switch closes. Repeat for the F and H points. Remove the card and insure each switch is open. Re-insert the card and re-check. A change of just 1/8 of a turn is typically the range for each switch to close and open correctly. Be patient, work slowly making small changes until all three open and close properly.
