Controllor failure, help please.

[stevew]

I have been asked by a friend to fix his child carrying trike;-



It's been left out in the rain and the controller was fill of water;-




When i opened it up water poured out. There was a fair bit of corrosion on the PCB. I tried cleaning it with WD40 and gentle scrubbing with an old tooth brush. It all looked better but still not working ! tried flushing it with meths and letting it dry but still no joy so i must assume it's toast !!

Next stop is to replace the controller but there are no plugs in the connecting wire so the question is;- Is it possible to fit a new controller of any sort?

Any help would be much appreciated.

Opps sorry guys, think i have this in the wrong section. Mods please can you move this to the tech area ?

 

[Deleted member 4366]

Yes. They all work the same. You just have to identify the wires:Yours will have five. They're:

• battery voltage from the controller, normally red
• battery voltage back to the controller to power it, normally blue. It becomes live when you press the on/off button.
• battery voltage for lights, which becomes live when you press the light switch, can be any colour, but maybe yellow
• signal wire to the controller to tell it what to do. It has 1v, level 1, 2v level 2, 3v level 3 and 4v for 6km/h, probably green
• ground 0v, black

You can test the controller by shorting the two that carry the battery voltage to and from the panel. Unless you're sure about the colours, you can confirm which is which by opening the controller. The one back to it will go to a pad marked VCC. Don't guess at the colours because if you connect a battery voltage one to the signal one, you'll blow the cpu.

The panel might come back to life when you dry it out, but on the other hand, the water inside might have shorted the battery to signal, so before ordering anything, check that the controller still works by joining those two wires. The throttle will work normally, but the PAS will default to level one.

If the controller doesn't work, you have to buy a new one. It won't be possible to repair it.

 

[stevew]

Thanks, im getting a 41v reading across the red and black but i guess i will have to short between red and which one ??

Actually i'll go and check the colors before anything else

Ok i have
Red
Black
Blue
Green
Brown (may be purple as those two colours often look the same to me!)

 

[Deleted member 4366]

I'm almost certain it's the blue one you have to short it to, but if you want to be 100% sure, you have to open the controller (not the panel). If you know about electronics, that looks like a MOSFET in the bottom right of the photo, which is what does the switching, so if the blue goes to one of its legs, it's definitely the one too.

 

[stevew]

Thanks Dave, job for the w/e i think

 

[VictoryV]

Any help would be much appreciated.

You could put it in a sealed poly bag, in a warm place, with about an 50 grammes of uncooked dry rice for a day or so. The rice has a high affinity for water and will dessicate the contents of the bag. That will remove any last traces of moisture

 

[stevew]

It's worth a try, cheers

 

[VictoryV]

It's worth a try, cheers

On second thoughts... if you have enought rice - bury it. You can still cook and eat the rice afterwards it will not be affected.

 

[Deleted member 4366]

Don't waste your time doing anything until you've checked that the controller works by shorting the blue and red wires.

 

[stevew]

Dave, I cannot see the blue wire going to the mosfet. The wires join the PCB bottom left in this picture and the Mosfet is at top left. The PCB route is impossible to trace !!



The red wire has corroded right through where it is soldered to the PCB so that's now disconnected and all the others look like they are about to follow !

Should i try shorting the red and blue when i cant be absolutely sure that the blue does indeed go to the mosfet?

The last option is to get another control unit panel and either splice the wires or try to find one with 2 meters of wire and the correct connector.





Pretty sure the controller panel is knackered.
Where should i look to get a replacement?

 

[stevew]

Just realised when i re-read the previous post that there may be a terminology glitch here !!

Thing with the LCD readout.................panel
Thing that is silver/ribbed and loads of wires coming out........controller

Am i right? Going to edit the previous post to read right

________________________________________________________

If i'm correct with this terminology are you saying that i should take the controller (silver thing) apart to see where the blue goes ?

 

[Deleted member 4366]

The thing that youve dismantled is a control panel and often referred to as the LED sisplay. The silver box is the controller, which provides and controls the motor. The control panel only tells it what to do along with the throttle and PAS, which are connected directly to it. Some controllers have LCD control panels that also show your speed and other stuff. LCDs normally give you many more options, such as the ability to set the maximum speed.

You won't see the blue wire connected to the MOSFET. You have to look at the point where it's connected to the printed circuit board, then follow the tracks to see where they go, bearing in mind that they swap from one side to the other through the holes in the pcb.

Your new photo shows that the flat black component in the corner is a 5v regulator, not a MOSFET, so the switching must be done by those two black transistors in the middle at the bottom of the photo. I can't see the wires, but the black will be on the pad marked "GRD" and the red "36V". the 36v will be connected directly to one leg of the transistor (via the tracks), and another leg will come back to the blue, which is attached to "DD" ?

 

[steve.c]

Any help would be much appreciated.

You could put it in a sealed poly bag, in a warm place, with about an 50 grammes of uncooked dry rice for a day or so. The rice has a high affinity for water and will dessicate the contents of the bag. That will remove any last traces of moisture

Did this with my iPhone after I dropped it in the bath?? Put a hairdryer on it first and then overnight in the rice and sorted???.