E Bike not working - KT Controller - KT LCD3 Screen - 36V

[Ballincollig75]

My E Bike is not running - any help appreciated.
I know I need a new PAS and have one ordered. Part of the Disc is cracked off of the old unit.
Throttle not working - i.e. nothing happening when twisted. As far as I can see the Hall Sensor is in the correct position - I cannot see any obvious way of taking it apart to check the magnets - anyone know how on this unit.
LCD3 Screen not staying on unless I keep the On / Off button pressed - The Screen is getting 41.6V when I have the Battery connected. I opened the 3 Button switch unit and found nothing wrong in that I had continuity from the incoming wires on different points of the circuit board. Also able to get continuity from the Switch back to the circuit Board in the Display unit.
The rear wheel Motor is stiff as it should be when I short out the phases going to it. Turns freely when not shorting the phases.
This is a Bike that was converted to an E Bike at some stage.

I have pulled apart all of the waterproof connectors and re connected them - no joy.
No joy whether the Brake signal cables are connected or disconnected.

See photos of the relevant bits attached.

 

[amberwolf]

First, what happened before the problems started?

If they started at separate times, what happened before each one started?

Knowing this in advance will help us help you find the root cause and fault so you can fix it.


(FWIW, almost always, there is something that happened to the device people come here to ask for help with, that they did not tell us about but was the key to helping them find the problem to fix it. Some of them even insist nothing happened, until some days or weeks down the line they say, well, nothing except for that crash, or that rainstorm, or that time it fell in a river, or that time they modified the wiring, replaced a connector, etc. )

I know I need a new PAS and have one ordered. Part of the Disc is cracked off of the old unit.

Does your system require you to pedal before the throttle will work? Some systems do, some don't.

Throttle not working - i.e. nothing happening when twisted. As far as I can see the Hall Sensor is in the correct position - I cannot see any obvious way of taking it apart to check the magnets - anyone know how on this unit.

What voltage does the throttle signal wire read while you are moving it? What voltage is on the 5v supply wire relative to the ground wire?

Often if you take it apart far enough to get to the magnets, they may fall out and you often can't tell what orientation they had been in. They must be in exactly the same one they were factory instaleld in or the throttle will not operate correctly or at all. If there are multiple magnets instead of just one, it can take a lot of trial and error to find the right combination of orientations to get the throttle to provide the correct output range again (by default, no field, it outputs half the supply voltage, typically). Some magnet sets are two tiny cubes, with (at least) six-squared possible orientations each. When i run into a throttle with magnets dislodged, and it's not just a single curved magnet, I scrap it and move on with a new one, because it would take me days to go thru the necessary trial and much much error.

LCD3 Screen not staying on unless I keep the On / Off button pressed - The Screen is getting 41.6V when I have the Battery connected. I opened the 3 Button switch unit and found nothing wrong in that I had continuity from the incoming wires on different points of the circuit board. Also able to get continuity from the Switch back to the circuit Board in the Display unit.

The switch has to be working or else pressing the button couldn't cause the display to turn on at all. They are just momentary switches.

The display has a transistor inside that is turned on by the MCU when you press that button, which turns the controller brain power on by sending battery voltage back to the controller LVPS. This may also provide power to the rest of the display to keep it on. If the transistor isn't latching on, then one or more of these is a likely cause:
--the MCU isn't telling it to latch
--the circuitry the MCU uses to do the latching isn't working
--the MCU detects some error at the controller or inside the display that causes it to unlatch so it can power itself off to protect against further damage or fire.

The first two would basically require a new display (which has to match your controller hardware and firmware to operate correctly; often it is easier to replace them as a set).

If the transistor isn't even turning on at all, then it's probably blown from overload (too much wired to it or too high a system voltage, etc), and that will keep the controller from turning on.

If the throttle doesn't get any supply voltage from the controller in the previous measurements, then it probably means the controller isn't powering on when the display turns on, so the 5v supply isn't working either.

Those issues often are caused by physical damage to wiring or controller, water intrusion into any of them (or the display), etc., and usually require replacing the controller/display/etc (whatever was damaged, which with water itnrusion and wiring faults often means everything).

 

[E-HP]

My E Bike is not running - any help appreciated.
I know I need a new PAS and have one ordered. Part of the Disc is cracked off of the old unit.
Throttle not working - i.e. nothing happening when twisted. As far as I can see the Hall Sensor is in the correct position - I cannot see any obvious way of taking it apart to check the magnets - anyone know how on this unit.
LCD3 Screen not staying on unless I keep the On / Off button pressed - The Screen is getting 41.6V when I have the Battery connected. I opened the 3 Button switch unit and found nothing wrong in that I had continuity from the incoming wires on different points of the circuit board. Also able to get continuity from the Switch back to the circuit Board in the Display unit.
The rear wheel Motor is stiff as it should be when I short out the phases going to it. Turns freely when not shorting the phases.
This is a Bike that was converted to an E Bike at some stage.

I have pulled apart all of the waterproof connectors and re connected them - no joy.
No joy whether the Brake signal cables are connected or disconnected.

See photos of the relevant bits attached.

If the display is acting up, you can bypass it for testing. You mentioned waterproof connectors, so given that clue, does your KT controller use the waterproof julet connectors and harness like this diagram? If so, you can bypass the display by jumpering the red and blue conductor on the display connector (red = battery +, blue = ignition) to turn on the controller.

You don't need to disassemble the throttle for testing if you have a multimeter and 5v for the throttle:

Guide to Hall Sensor Throttle operation, testing, and modification. - Electricbike.com Ebike Forum

***** 8-16-2018 Welcome to the Hall Sensor Throttle Thread! If there is something you'd like to add, correct, needs better explanation, or have a question about... feel free to Private Message me. Better yet, open a new thread in the "Trouble Shooting...

electricbike.com

How are you able to "see" the hall sensor in the correct position??

 

[Ballincollig75]

Amberwolf & E-HP

Thank you very much for the most informative information.

I have only recently acquired this bike.

First, what happened before the problems started? The PAS has not worked since a piece broke off of the Disc - new unit ordered - due in about two weeks.

If they started at separate times, what happened before each one started? The Throttle had been operating but not giving the boost it should for some time - now nothing coming from it.

How are you able to "see" the hall sensor in the correct position? I removed the triangular cover to look at the wiring - it looked like the Hall Sensor was almost out of its holder - I pushed it back into position.
MCU?
LVPS?
Does your system require you to pedal before the throttle will work? Some systems do, some don't. No.

22/04/25

Having read the information I received yesterday from you I jumpered the Julet Cable coming to the Screen and to my delight found the following;

Throttle working and now has far more boost with the Hall Sensor now fully in position.
PAS now also working despite a piece being cracked off of it - I had taken it off last week and separated the two sections of it and cleaned them - It is currently set on the display at level 5 when connected.

Is there anything I can do with the display unit to try and get it operational / communicating properly again?

I have only just joined the Forum and to get a result and help like this on day 1 is fantastic and much appreciated.

Kevin

 

[E-HP]

You probably need a new display. If you get one, get the exact same model. Alternatively, if the bike performs the way you want it, you can just run without a display and replace the jumper with a toggle switch to turn the system on and off.

How did the PAS disc break? Did you have a crash?

 

[Ballincollig75]

I do not know as it was that way when I got the Bike a few weeks ago. Thank you.