Burnting circuit board

[Andrew Wingrove]

Hi, I am trying to find out what is burning out a component on the control unit for a Izip Skyline Electric Bike. The unit was replaced and it did the same thing on the new one. The type of control unit is shown top right circled in yellow and the burnt out components are circled in red.

 

[Deleted member 4366]

Not enough information yet. The photo of the display unit is too blurred to read the writing on the switches and I'd need to see the other side of the PCB.

If you want me to take a wild guess, it's a mosfet to switch either the lights or the main power, which means that you have a short on one of those lines. Did it blow straight away? If not, what were the circumstances?

Have you over-volted your controller? What voltage is your battery?

 

[Andrew Wingrove]

Hi, Thank you for responding to my question. I brought the bike home today and can now start to find out more information. You did go into depth with one of these units once before and I found some information here. http://www.pedelecs.co.uk/forum/threads/izip-skyline-shut-down-problem.15229/page-2

According to the person I bought the bike from he indicated the component as the FET?

Quote from him "On the back of the circuit board on the handlebar control unit there is a small electronic component that has burnt out. Believing this to be the problem I sourced a replacement control unit (£45.00) and connected it up only for the same thing to happen again. The battery shows full charge." This is the photo he took. ( garden in the back ground )

In your previous article you wrote.

"The red wire is the 24v supply.

• The pink wire is switched on to the 24v when the panel is on.
• This 24v then goes back to the controller to supply the 12v regulator, which then supplies the 5v regulator.
• The black wire is 0v

- The blue and purple wires are TX and RX data to the controller.

The 24v comes in to a FET, which blocks it.

There's a branch to the power switch, which when pressed opens the FET to pass the 24v through the big resistor to the 5v regulator, which then powers the main processor.

The main processor then gives an output to a small transistor that latches the FET on.

When you press the power button again, the processor logic switches off the small transistor which then switches the FET off again, so everything powers down.

There's a voltage splitter that gives a voltage measurement to the processor. It uses logic to switch on/off the battery LEDs.

The PAS level switch is also sensed by the processor, which then uses logic to switch on/off the PAS level LEDs, and at the same time sends data to the controller to set PAS levels.

There could be some hand-shaking procedure between the controller and panel necessary for the controller to start operating as there is TX and RX.

The power section works the same.The red wire is battery voltage, the blue the return to the controller power, and black 0v, but the forth wire (green) has an analogue output. Pas level 1 = 1v; Pas level 2 = 2v; Pas level 3 = 3v; 6km button changes output to 4v when pressed."

I have uploaded the two photos from the article that show the front and back.



Would my first move be to charge the battery fully and then check the voltages on the red and the pink wires to make sure its 24 V and then 0V on the Black, Blue and Purple.

 

[Andrew Wingrove]

Not enough information yet. The photo of the display unit is too blurred to read the writing on the switches and I'd need to see the other side of the PCB.

If you want me to take a wild guess, it's a mosfet to switch either the lights or the main power, which means that you have a short on one of those lines. Did it blow straight away? If not, what were the circumstances?

Have you over-volted your controller? What voltage is your battery?

Hi

I have just bought the bike as a non runner to fix for myself, so not really sure of all the circumstances. The battery is 24 Volt and is the original battery for the bike.

 

[Deleted member 4366]

AFAICS, the burnt mosfet is what switches on the pink wire. The reason it burns is almost certainly that the pink is drawing too much current through it. That would be because the pink wire is shorted to ground somewhere or there's a short inside the controller. I would open the controller and look in there. The pink wire provides the power to run the controller, the throttle, the motor hall sensors and the PAS. It does not provide power for the motor.

It does the same as the red wire in the LED panel. It goes to a big resistor, then a 12v regulator, then a 5v regulator. Have a look at the big resistor, which would look burnt if a lot of current went through it.

I still need to know what the markings are on the top cover

 

[Andrew Wingrove]

Hi, I have taken photographs of the control unit and the controller. In the main controller the circuit board is set in a clear resin with just the wires secured by the resin before they reach the board. I have removed the handlebar control unit and there seems to be no damage to the cable or connectors. The battery is a 24 volt battery that is putting out 24.9 Volts when tested at the power connector to the controller.

 

[Andrew Wingrove]

Hi

I tested the controller last night and with the black on black and red on red connector to the handlebar controller unit initially had about 7 volts, which over a period of 25 minutes increased slowly to 24.9 Volts. When I removed the battery from the bike there was still the same voltage showing on the red cable which over a period of 10 minutes had dropped to 22.4 Volts. there was no reading from any of the other wires. Do you think I need to replace the main controller, as I don't think half an hour to reach the full power of the battery to the LED controller can be right.

 

[Deleted member 4366]

I don't understand what you did, but the controller gets it's power from the LED control pane. With that burnt mosfet, you can't switch on the controller. The battery wires connect to the controller, but they don't actually power it. thhere's a branch on the inside of the controller that goes up to the switch on the LED panel, then back again.

You can run the controller without the panel by bridging the red to the pink wire, but I suspect that you have a short somewhere, so I wouldn't advise that without taking precautions. Maybe use a 0.5 amp fuse between them. if it blows, you know you have a short.

 

[Andrew Wingrove]

Hi, I have bitten the bullet and ordered a suitable controller and LED online to replace this one. In the attached photo circled in yellow is the connector that the LED plugs into. with this all attached to the bike I was taking reading from this connector, ( without the LED attached ) Black probe on the black wire and red on the red wire.

 

[dgncsk]

isn't that a voltage regulator? i burnt very similar one on arduino mega while trying to set my 3d printer.

 

[Deleted member 4366]

The regulator is on the other side of the board. You can see it in the middle at the bottom of the photo.

Also, you can see one leg is connecteded to the red wire (battery positive) and the other to the pink, which is the wire that powers the motor controller. The gate is connected to a small transistor that switches the gate voltage.