Diagnosis help

[spanos]

Hi all , I’m looking at a fairly standard 36v rear hub setup that had a sudden total power failure

I’ve check battery, outputting full 42v
I’ve checked the controller is getting power, fine
I’ve checked power is going to lcd , fine

I’ve checked the remote switch (see pic) which is getting full voltage to red and black)

But still lcd won’t switch on

So I’m thinking either switch or lcd has packed up

If I connect red to black on the switch will this bypass it and turn on lcd ? I presume the other two wires are signal wires for the up/down pas level. No throttle on the bike (though the controller seems to have the plug for one ) I

Main lcd plug at controller

Lcd underside (right side goes out to remote switch )

And the remote switch innards

Thanks all

 

[Deleted member 4366]

Do not connect red to black unless you want a fire. To bypass the LCD, you need red to blue for power and green to yellow for data. I doubt that that will work.

You need a voltmeter to check where you have battery voltage. If the LCD doesn't come on, it's because it's not receiving battery voltage from the red and black wires, so you need to trace back where the interruption is. Check the battery to controller connection, and if there's no voltage there, then it has to be the battery terminal connection.

The LCD red and black wires branch directly from the main red and black battery wires inside the controller.

 

[spanos]

Do not connect red to black unless you want a fire. To bypass the LCD, you need red to blue for power and green to yellow for data. I doubt that that will work.

You need a voltmeter to check where you have battery voltage. If the LCD doesn't come on, it's because it's not receiving battery voltage from the red and black wires, so you need to trace back where the interruption is. Check the battery to controller connection, and if there's no voltage there, then it has to be the battery terminal connection.

The LCD red and black wires branch directly from the main red and black battery wires inside the controller.

Hi, I don’t think I’m being clear .let me try again

I have 41.5v from battery. Then same full voltage leaving the controller to the lcd panel (putting multimeter probes down back of the plug on red and black)

And again I get full voltage on the remote switch red and black

I have not taken the lcd apart but the wire from the controller goes into lcd and then out again to the remote

Does that make more sense ? The lcd must getting full voltage as the remote switch is reading voltage and the wiring goes to the lcd first .

 

[spanos]

Problem solved. It’s the lcd itself

New one plugged in. Bike fixed

 

[Deleted member 4366]

Probably the battery wire pulled off or broken off its pad.

 

[spanos]

Probably the battery wire pulled off or broken off its pad.

That’s what I figured but the five lcd wires from co troller had full voltage on the lcd pcb when I took it apart . So connected . More than that those five wires exit the lcd pcb as 4 wires that go to the remote on/off switch .

That switch also had full voltage . All wires tested for continuity ok right back to controller

My conclusion was a component on the lcd pcb had gone.....likely due to water ingress (though not evident )

All solder joints to pcb pads were sound