Quinton ST 55 Service Manual page 39

RepairIReplacement and Calibration
Reassembling Install new rack gears at the same time so that they extend an
the Rack Gears equal distance through the headframe.
1. Restore power to the treadmill.
2. Loosen the setscrew that secures the grade potentiometer gear
and remove the gear.
3. Put the ECG monitor into service mode.
4. Insert rack gears into headframe.
5. Decrease the grade until the gears bounce two or three times,
then increase the grade. This should cause both rack gears to
mesh in exactly the same place.
6. Run the rack gears down past the bottom of the headframe.
Hold the limit switches closed to let the rack gear travel beyond
its normal lower limit.
7. Check below the headframe to verify that the rack gears are
meshing properly. The gears should protrude an equal distance.
8. Run the rack gears down
until there is enough room to replace
the wheels.
9. Bolt the wheels to the rack gears.
Replace washers used as spacers in the correct arrangement.
Torque the bolts tightly to 46 ft-lb
+4
ft-lb.
10. Increase the grade until the wheels touch the floor.
11. Grease the rack gears with wheel bearing grease.
12. Remove the blocks that support the headframe.
13. Reinstall the grade pot bracket and assembly.
14. Calibrate the grade potentiometer.
15. Turn the treadmill power off, remove the power cord from the
outlet, then reinstall the hood.
ST 65
Leftside Limit Switch Locations