705 classic controller leds flashing

Chris Maluszynski

Pedelecer
Jan 26, 2015
217
1
49
I have a 705 Classic with some kind of electronics issue. When bike is turned on, first the lights on the led display go up and down in the startup procedure. Then the first capacity led starts blinking for maybe 5 seconds, and after that all the power indicator leds start blinking (the first capacity led keeps blinking also).

Where should I start troubleshooting?

Thanks!

Chris
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
20,917
8,533
61
West Sx RH
Bike manual should tell you via fault diagnosis one would think.
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
9,822
3,993
Basildon
The first thing I'd do is disconnect the control panel, then try to run the bike without it by bridging the red and blue wires to see if the controller and motor work.

The mode of failure would give a good clue to what might be faulty. How did the problem start? What caused it?
 

Chris Maluszynski

Pedelecer
Jan 26, 2015
217
1
49
The first thing I'd do is disconnect the control panel, then try to run the bike without it by bridging the red and blue wires to see if the controller and motor work.

The mode of failure would give a good clue to what might be faulty. How did the problem start? What caused it?
Would you disconnect it at the controller?
I bought the bike with the fault so don’t know how it started. I think with no apparent reason according to the seller.
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
9,822
3,993
Basildon
Would you disconnect it at the controller?
Yes. You can only bridge the pins if you have the flat black type connector, not the moulded type.

Which LED display do you have? The low PAS level LED flashing on a 790 means over-current, which would be a blown MOSFET in the controller, damaged motor cable or motor connector not fully in, so if it is a 790, you need to check those first to avoid burning something.
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
9,822
3,993
Basildon
I've just checked the Wisper manual:
The first light flashing is over-current.

Disconnect the motor and battery from the controller and measure the resistance between the red battery wire and the three motor phase wires, then repeat for the black battery wire. Each group of three should be the same and in the range of 7K to 14k. The actual result isn't important as long as all three are the same. You might find that one set continuously climbs due to the capacitor charging from your meter. That's no problem as long as all three behave the same and give similar results.
 

Chris Maluszynski

Pedelecer
Jan 26, 2015
217
1
49
Ok. I just peeled off some electrical tape on the cable to the display. Looks like this may be the cause. I will try to patch it together and see if it works. But I also have a KM529 display laying around - could it be substituted for the old wisper display? I see it only has 5 pins where the wisper has 6 (and a different plug). So maybe not?4210542107
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
9,822
3,993
Basildon
If either of the two battery voltages wires touch any data or signal wires, you wipe out the control panel and/or the controller.

If it doesn't work after repairing the wires, you have to disconnect the control panel and bridge the two battery voltage wires, which will switch the controller on without it so that you can test that the controller still works.

Don't connect that other control panel unless you have confirmed that the correct wires connect to it in the correct sequence.
 

Chris Maluszynski

Pedelecer
Jan 26, 2015
217
1
49
It worked after twisting the wires together. It’s a temporary fix though so will need a new control panel eventually. Would another type work for this bike? Or can I get a replacement from Wisper somehow?
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
9,822
3,993
Basildon
That's not so common. I'd guess that's the power, ground, switched controller power, Rx, Tx and lights, but which is which? You'd have to open the controller and/or control panel to check the board markings to see which is which. before you could try a different digital control panel.

If it were mine, I'd make an opportunity out of a crisis and replace the controller for a better one with an LCD. Then you'll where you are and be master of your desiny and bike, or simply leave it as it is if it's working.
 

Advertisers