Trouble-Shooting - biodex 950-387 Application/Operation Manual

12. TROUBLE-SHOOTING

SYMPTOM
Gait Trainer is turned ON and speed control is inoperable (belt not moving).
1. Check for faults on display unit before moving onto step #2. The following diagnostic
error codes apply:
CODE DESCRIPTION
128 Communication between upper/lower board inop
64 Safety Lanyard Removed
32 Control fault (no amplifier)
16 Grade Error
8 Motor Tach Output Exceeds Selected Speed
4 Motor Tach Output is Below Selected Speed
1 Hall Sensor Output is Below Selected Speed
2. If no faults are displayed check the following:
• Large blue capacitor should measure 170 VOL across terminals. If OK, proceed to step 3.
• Speed control signal on motor amplifier should measure .250 VDC per mill per hour E.G.
NOTE: Measurement taken at J1 Pin 1 PIN 2
If speed control signals are OK, proceed to step 3.
3. Check Amplifier Output. The Output Terminals are located on top of amplifier and are
designated "m+" and "m-". The Output voltage should be: 1mph = 32 VAC, 2mph = 52 VAC
NOTE: Remember to use the volts A.C. selection on your meter. The Amplifier is pulse width
modulating, therefore A.C. scale is required.
If amplifier output is OK, proceed to step 4.
4. Check Motor Resistance. The motor has a winding resistance of 1.3 to 3 Ohms. The
value is dependent on commutation position. If resistance reading is significantly higher
the windings or brush contacts are defective.
To measure resistance turn Gait Trainer power OFF. Place meter lead across terminals
marked "m+" and "m-". Set meter scale to the lowest resistance selection. Check resistance
in several commutator positions by rotating motor shaft 9.0 degrees for every one revolu-
tion.
1mph = .250 VDC
2mph = .500 VDC
4mph = 1.00 VDC
8mph = 2.00 VDC
— 12-1 — TROUBLE-SHOOTING