KTLCD3 V301G 24/36/48 not staying on

[Ballincollig75]

I have the above Screen / Display on my E Bike - the display will not stay turned on - I need to hold the On button for the screen to stay live. The button pad clicks as you would expect it to but the screen does not stay on and consequently I cannot scroll through the settings. I have disconnected and re-connected the waterproof connector - no joy. Any ides what I should do?
I did put a cable tie around it to hold the On button pressed this is the only way to get it to stay on. In riding the bike the other day without the Battery on board - the screen would come on when I was going at a certain speed - obviously getting power from the Motor - but go off again when I slowed down.

 

[harryS]

The three button unit supplied with the LCD3 uses momentary contact switches, If it has to be held down, that probably means the LCD3 circuitry is at fault. There is no speed or battery data is there? Does the thermometer work?

Use the runner band while you order a new LCD3. U think the LCD3 is a better than their smaller color displays, which are hard to read. The LCD8H is probably nice, but too expensive for me.

If you want to be adventurous, you can remove the LCD3 and jumper the controller to run without it. I think that is what is happening when you hold the button down. With the non waterproof LCD3, KT provides a plug to do that.,

 

[Ballincollig75]

Battery data - yes. Showing a full battery which I know is correct.
It was also showing a full Battery the other day when I was cycling without the Battery on board - it came on briefly when I was going fast enough - showed a full Battery.
Should the bike function as an E Bike with this unit in situ without the screen on?

 

[harryS]

Should the bike function as an E Bike with this unit in situ without the screen on?

When a KT LCD3 powers up, ir puts 36V on the control pin, If your bike is 48Vm then it puts 48V there,
When the controller sees that voltage, it powers up,

The LCD3 then sends data ti the controller, and gets data back, This data initializes the PAS level you picked in the LCD3 for startup, It also sends some of the other parameters for pedal assist strenth and max current that you put into the C-parameters of the LCD3.

If the controller doesn't see any data from the display, it reverts to am active throttle and a single PAS level.

Yes, a KT controller can run the ebike if the controller is mute or missing, as long as the control pin has battery power.


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[Ballincollig75]

Harry. Thank you. I can confirm that the female lead coming to the display is getting full voltage - mine is a 36V Battery currently showing voltage of 41.6 at the Battery and also at the Julet connection for the display.
I will try and open the 3 Button unit attached to the display and check for a loose wire- nothing to loose.

 

[Ballincollig75]

I opened the On Off switch - no apparent issue here - continuity on the C Board and also back to the C Board in the display.

 

[Ballincollig75]

22/04/25 Update

I got some help on a different forum - to jumper the 36V & Control on the cable coming to my screen. I did this and to great relief I now find that the Throttle is working as it should (I had opened the triangular section of this the other day and it looked like the Hall Sensor was almost completely out of position - I pushed it back in place) and the PAS is also working. It looks like I need a new Screen display and Button unit or else put a permanent jumper in position and go without the display for now. Anything else to check for on the Display before I bin it?

 

[Ballincollig75]

14/04/25 Finally after a long wait the new Display (KT LCD4) arrived from China this week. Connected to the Bike and found that the Throttle worked fine with it but the PAS was not working with it. Disconnected the LCD4 and jumpered the connection to find that the PAS was not working in this manner either. Installed the new PAS connecting it to the Julet connection of the old unit - Red was the only common cable - trial & error to match the other two - PAS now working - soldered the connections and weather proofed. The Bike is now working as it should - PAS and Throttle fine. Thank you for the assistance.