Damaged kt-lcd3 screen

djah

Pedelecer
Apr 24, 2018
59
1
49
Ireland
Hello. It appears that I may have damaged my screen. I was testing my motor hall sensors and I think I put the probe from my fluke somewhere I shouldn’t have.
The screen comes on when I press and hold the power button but will not stay on when I let go. I was just wondering can they be repaired? Are there any serviceable parts inside or should I just bin it? Thanks.
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
7,495
2,856
56
West Sx RH
Testing motor halls shouldn't affect screen or cause damage if you only probe on the motor side of the controller.
Likely hood is that you may have shorted something in the controller.

You can carry out lcd test.
Connect everything up.
On the LCD connector, bridge red to blue & green to yellow.
If lcd is faulty the motor will work, If motor doesn't work then controller or motor are faulty.
 

djah

Pedelecer
Apr 24, 2018
59
1
49
Ireland
Thanks. Nealh.
I have tested the display on my own bike where everything is known to be ok and the screen is faulty. Just to fill you in on the background. The initial problem happened on my wife’s bike when she was going up a steep hill. I guess she got tired and applied full throttle. Everything stopped and she got info 3 error which is for hall sensors.
I got a replacement motor which worked ok for a while but failed again in pretty much the same situation.
When I was testing the hall sensors I got a bit of a spark from the probes and after that the lcd screen wouldn’t stay on. At this point I thought I damaged the controller so I purchased a replacement along with a replacement motor. When I fitted these I still had the same issue with the screen along with a faulty throttle which I hadn’t noticed before.
So to wrap up, I have a working motor and controller and a faulty lcd screen and throttle.
Any ideas?
Thanks.
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
7,495
2,856
56
West Sx RH
Without opening the lcd (if you can open it) you won't know if a fault is visible. could be a burnt out switch wire as they only carry low amps or a diode or resistor might show up as damaged. Easiest option is to replace lcd.
Your spark from hall testing may have been that you accidently shorted the two probes when connected to the wiring.

Throttle you don't say what is wrong again only two faults with a throttle I can think of ;
1. Hall sensor failed.
2. Intermittent throttle power ( wire brake causing poor contact).

For hall testing carefully as long as probes don't short to each other no sparking should occur. If poss have a spare pair of hands to operate throttle when needed.

With power on check at throttle connection;
1. 5v between V+ & Gnd is normal voltage and will show up if controller is fine.
2. 1v between Gnd & signal, if 0v hall failed.
3. 4-5v when throttle opened.
 
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