2-1. Display Malfunction Troubleshooting Table - C520U/C531U
Malfunction
Circumstance
Inspection and Test Points
Suggested
Components
Notes
Cannot
start unit
The display is not
lit; I pedal the
bike; but the
display still
doesn’t light.
1. Inspect cable connections.
2. Inspect drive board fuse.
3. Inspect drive board power LED.
4. Inspect the alternator.
1. drive board
fuse
2. drive board
3. alternator
Cannot
start unit
When I don’t
pedal the bike, the
display does not
light.
1. Inspect battery fuse on the drive board.
2. Measure battery voltage. Battery voltage should be 5.5V
or more.
3. If battery voltage is under 5.5V, pedal the unit at over 50
RPM to recharge the battery.
4. Replace the battery if voltage is under 2.0 and it won’t
recharge.
1. battery fuse
on the drive
board
2. battery
Display
won’t
operate
I start pedaling
the bike, but the
display shows no
reaction, and
values don’t
change.
RPM signal didn’t enter the display IC. Inspect RPM signal.
1. Inspect cable connections and the bridge board.
2. Inspect the reed switch and magnet.
3. Inspect the drive board CLK LED.
4. Inspect the reed switch and its wire.
1. magnet
2. reed switch
No
resistance
I pedal the bike
and press
resistance keys.
Resistance values
on the display
change. But there
is no resistance.
1. Inspect cable connections.
2. Inspect alternator startup. If alternator will not start unit,
there will be no resistance.
3. Inspect the electro-magnet and its wires.
4. Test whether the drive board emits voltage to the
electro-magnet.
1. drive board
2-1-1
