Replace / Upgrade of lcd 790 display & controller.

[vfr400]

Good luck. keep us informed.

If it doesn't work, but you do get a reaction from the motor when you move the magnet disc over the sensor, remove every other magnet, so that there are only 6.

 

[orcecaveman]

Will do. As soon as I get the replacement I'll update again. The magnet disc on there at the moment has 12, so I'm hoping itll be an easy swap and all will be fine, but we'll see.....
I did have another fiddle tonight. I put the sensor back on and moved the magnet disc as close to it as I dared. Still the same, nothing.

 

[Speedee]

Do these bikes have a throttle? Not sure if you mentioned it. If so, does the controller respond to the throttle?

 

[orcecaveman]

No throttle.

 

[orcecaveman]

Hi again.
Well I've an update... today my new pedal sensor arrived. It's a King-Meter and is identical to the original one.
Well....... drum roll..........




No bloody difference at all. I have 4.75 volts at the plug from the red and black wires, but just as before nothing at all from the black and green wires when pedaling, not forward or reverse. I've inspected the plugs and wires and I'm sure they are fine.
So....... Where too next guys.... PLEASE HELP!

 

[Speedee]

Very strange. Do you have a multimeter instead of that voltage meter you are using? If not, can you borrow one? Did you get a pas sensor with a magnet disc? If you did, try that disc with the sensor. If not...think something might have happened to the magnet disc on the bike?

 

[vfr400]

You need to turn the pedals really slowly to test it and see the 5v switching on and off.

If it still doesn't switch, remove the signal wire pin from the connector and test it unconnected. To do that, you have to insert a tiny jewellers screwdriver or a sewing needle into the slot adjacent to the pin (right next to it, not the one nearby) to depress the barb, then you can pull the pin out from the back by tugging the wire. It takes a bit of manipulation to depress the barb. Reset the barb before you put the pin back in the connector.

 

[orcecaveman]

Thanks again for your help!

Ok , I've binned the voltage gauge. Now it gets weirder.
So, I'm using a decent quality (Sykes Pickavant) multimeter.
I'm getting 4.7 v from the red and back, but I'm also getting 4.7v (steady) from the black and green. I've turned the pedals slowly, backwards and forwards. Checked the magnets on the disc and they are all fine and magnetic....

 

[orcecaveman]

Thanks for being patient. I swear it's not a wind up!

 

[Speedee]

What do you get when the sensor is plugged in but not anywhere near the magnet disc? Also try measuring with the signal wire unplugged as suggested. If you still get a continuous output on the signal wire I wonder if the controller spikes on power up. That might fry the hall sensor.

 

[orcecaveman]

What do you get when the sensor is plugged in but not anywhere near the magnet disc? Also try measuring with the signal wire unplugged as suggested. If you still get a continuous output on the signal wire I wonder if the controller spikes on power up. That might fry the hall sensor.

I'll try in the morning. When you say the signal wire, do you mean the green one?

 

[Speedee]

Yes, the output wire which is green in your case.

 

[orcecaveman]

Thanks I'll report back tomorrow.
I really appreciate all the help from you guys.

 

[vfr400]

Did you check that the connector has black to black and red to red wires?

 

[orcecaveman]

Right I've dived in the deep end this morning and unearthed (what I think) is a horror.

1. First off, something I've been thinking about for a while... the previous owners name is written on the controller. Maybe a sign that it's been in a shop or somewhere to be fiddled with?
2. A much closer look at the wiring and I noticed some insulating tape which hid the wires for the lights 'twisted' onto the yellow and white wires from the display unit.

3. So I've taken the bull by the horns and removed the controller and all the wiring from the housing. I had to cut one of the multi plugs off to bet it through the hole.

4. I've ordered a new controller, display and thumb throttle:

Lcd6 Display:

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Controller:

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Thumb throttle:

US $4.46 |Accelerator Speed Control Electric Bike ABS Metal Thumb Throttle Scooter Accessories Black Replacement Practical 3 Wire Grip|Electric Bicycle Accessories| - AliExpress

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5. I've attached some pics of the wiring I have. Hopefully it'll be a straightforward job of just replacing with new?
The only original components will be the motor and battery. I'm sure the battery is fine, but is there a way that I can check the motor, bearing in mind that i now have nothing connected to it apart from the wiring loom?

Thanks again in advance for taking time to help me. !!!!!!!!.


I wonder if I'll find the same with bike number 2 when I get it here?

 

[vfr400]

You're barking up the wrong tree. A new controller will not fix a PAS that is apparently not switching. You confirmed that it had a 5v supply. That's all the controller needs to do. If you had done the tests I suggested, you would have an answer to your problem. They're simple.

1. Check that the red goes to red and black goes to black.
2. Remove the signal wire pin from the connector. Confirm the 5v on the red and black. Check the voltage on the signal wire. If its not switching, no controller in the world will change that.

In future, you don't need to cut connectors off when they don't go through a hole. The pins are easily removable from the block. Without the block, they go through the hole.

The twisted wires were for the lights. That has absolutely no affect on the function of the controller. The lights are powered and switched by the control panel directly from the battery.

The money on the new controller isn't wasted. it'll make your bike much better. for the sake of a couple of quid, you should have got the PAS with the controller to guarantee the right connector and connection sequence. The cheaper PASs always give fewer problems and I challenge anyone to tell the difference in function between the different ones in a blindfold test.

Just noticed one other important thing. You need the speed sensor that goes with the LCD and controller if you want the speed to display correvtly. without it, the speed will go to zero every time you free-wheel or ride on level zero.

 

[orcecaveman]

I've just opened the controller. I'm thinking that this isnt a good sign....

 

[orcecaveman]

You're barking up the wrong tree. A new controller will not fix a PAS that is apparently not switching. You confirmed that it had a 5v supply. That's all the controller needs to do. If you had done the tests I suggested, you would have an answer to your problem. They're simple.

1. Check that the red goes to red and black goes to black.
2. Remove the signal wire pin from the connector. Confirm the 5v on the red and black. Check the voltage on the signal wire. If its not switching, no controller in the world will change that.

In future, you don't need to cut connectors off when they don't go through a hole. The pins are easily removable from the block. Without the block, they go through the hole.

The twisted wires were for the lights. That has absolutely no affect on the function of the controller. The lights are powered and switched by the control panel directly from the battery.

The money on the new controller isn't wasted. it'll make your bike much better. for the sake of a couple of quid, you should have got the PAS with the controller to guarantee the right connector and connection sequence. The cheaper PASs always give fewer problems and I challenge anyone to tell the difference in function between the different ones in a blindfold test.

Just noticed one other important thing. You need the speed sensor that goes with the LCD and controller if you want the speed to display correvtly. without it, the speed will go to zero every time you free-wheel or ride on level zero.

Thanks for the reply, I did try the tests again with the PAS this morning and it was the same. I didnt bother removing the signal wire as I decided to go for a new controller.
I chopped the wires because access was limited in the housing and I will solder the wires (as you advise) when I reinstall.
I did wonder about getting a new PAS and speed sensor. Do you have any recommendations please?

 

[vfr400]

That resistor often gets hot. It can tolerate a bit of burning. It gets hottest when something is wrong, like a short on the 5V, which can be in the throttle, on the PAS, a motor hall sensor, etc. Misconnection of any of the 5v devices could do that, like if you had the wrong connection sequence on the PAS connector. You still haven't confirmed that you checked that.

 

[orcecaveman]

That resistor often gets hot. It can tolerate a bit of burning. It gets hottest when something is wrong, like a short on the 5V, which can be in the throttle, on the PAS, a motor hall sensor, etc. Misconnection of any of the 5v devices could do that, like if you had the wrong connection sequence on the PAS connector. You still haven't confirmed that you checked that.

Sorry, I can confirm that I definitely checked that, not once but several times. Black to black , red to red.
This is the adaptor I made so that i could connect my multimeter
Thanks everybody for being so patient.