Magic Pie 4 won't react to thumb throttle

[Bikemad]

I changed the phase wires to quick disconnects, assuming the colors were the same with the new controller and let the hall sensors connector loose inside the wheel (I think the GM controllers work sensorless if the hall sensors are shot).

Unfortunately, the Vector controllers do not have a sensorless mode, therefore the Hall sensors must be connected for the controller to work.

If the MP4 controller is no longer available, the standard MP5 controller or Bluetooth upgrade kit can be used instead.
However, you may also need to change the connectors on the Hall sensors and phase wires if they are not the same.

The Hall sensor plug will need to be replaced with the correct connector assembly to suit the new controller:

I measured the resistance between all phase wires: about 30k whatever the colors. Strange ...

The resistance between each pair of phase wires should only be a fraction of an Ohm, definitely not 30,000 Ohms! 

Alan
 
 

[Asterix]

the failing resistance test could be in fact a "good news": may be the old controller is still working perfectly well and the problem is "just" related to some wiring defect.

[Speedsterharry]

I installed the new controller in the wheel, while taking care of the hall sensors connector (hopefully in the right order): same symptoms as before ...
So I think there's something else not working. Since the Vector controller has no sensorless mode, I'm tempted to think one of the hall sensors is dead (would that mean the wheel will not rotate ?). This could be good news because in that case, the old controller might be completely functional. I haven't had the time to test the halls so far. Will do so on tuesday.

As for the 30k resistance, I was talking about two phase wires on the controller side, not from the wheel side (where I get a sub ohm resistance between any 2 phase wires). Sorry for not being clear in my description 

Thanks for the suggestions, Asterix and Alan, they give me some things to test.

[Speedsterharry]

I detected a failing Mosfet on the Yellow phase (on the old controller). All the FETs are fine on the new one of course.

I still couldn't check the halls, the test is pretty difficult to convey even with 2 people. I can't access the hall sensors now because the screws holding the motor flask went out of shape when trying to open them, now they are stuck. I Used a drill and drill bit to get rid of the screw heads but there must be some metal left over that holds the lid closed. The motor isn't pretty anymore, I have no clue how I will get the flask closed with watertightness.

Asterix:Are you french by any chance ? I can give you the old MP4 controller if you wish to have a look for a fix, or take photos of the MOSFETs if you can access them.

[Asterix]

yep Speesterharry, Asterix is "un Gaulois".
Best thanks for your offer.
Let's first send me some high resolution pictures of the MOSFETs, I will try to see what can be done.
See your private messages.

[Speedsterharry]

@Asterix: My offer was to send you the broken controller (for the price of postage) and YOU take some photos of the mosfets (I can't access them). If you can devise a way to fix the mosfets and let these forums how to do it (with photos), it would benefit the community. If that can help others ....

[Asterix]

ok, no problemo and many thanks for your offer. I will try to access the mosfets and will publish the results of the investigations here so that it can benefit to the community.
See private message for contact via email.

[Speedsterharry]

I finally found the time to test properly (I think) the hall sensors, with 2 Li-Ion accus in series (around 8V in total)

HS#1: around 7.9V (steady)
HS#2: around 7.9V (steady)
HS#3: 0 V (never changes)
Done while slowly turning the wheel around the axle

Those readings would mean all 3 sensors are shot ?!? It doesn't matter, I bought 4 replacement hall sensors (SS41).

The only problem is to open the flask. I had 2 screws that were stuck in their place, I tried drilling their heads, thinking that this would free the flask, I was wrong. What could I do to now ? See photos for current state of the flask ...

Asterix sent me a set of photos in private of my dead MP4 controller and managed to get access to the mosfets, I hope he can find the time to post the photos and some instructions to replicate what he did.

[Asterix]

yes, thanks for the reminder Speedsterharry.
This was the controler at beginning:

[Asterix]

So as you can see there is some gel, glue that maintains the components inside the aluminium housing.
The trick for opening this stuff and get acces to the mosfets, is to use some screwdriver and to slowly push the board outside the housing:

[Asterix]

then you put the gel outside as much as possible

[Asterix]

the problem is that you also destroy some copper wires by doing this...see first picture below.
Also I made a mistake that should not be done: before using the screwdriver, I have unscrewed the screws...bad idea: those screws do not fix the board to the housing.
They are just soldered to the boards, so by unscrewing them...you destroy the copper wiring of the boards.
Hope those advices can help the next person that tries to open such a controler.

[Bikemad]

The only problem is to open the flask. I had 2 screws that were stuck in their place, I tried drilling their heads, thinking that this would free the flask, I was wrong. What could I do to now ? See photos for current state of the flask ...

If you are not using disc brakes, then simply refit the cooling fan/disc mount with the four good screws, as this will be more than adequate to hold the cooling fan in place.

However, if you have a brake disc rotor mounted to the cooling fan, four screws are not really strong enough to cope with the tremendous side loads exerted upon the screws, and there is a chance that the remaining four screws could sheer off completely under heavy braking. 

If you are intent on using a disc brake with only four of the six screws, I would suggest permanently bonding the cooling fan/disc mount onto the side cover flange with some suitable metal adhesive in addition to the four remaining good screws.

Ideally, the side cover and the cooling fan/brake disc mount should be replaced, unless you are able to have new holes drilled and tapped with the required thread adjacent to the damaged ones, which would then allow all six screws to be used.

Alan
 

[Speedsterharry]

If you are not using disc brakes, then simply refit the cooling fan/disc mount with the four good screws, as this will be more than adequate to hold the cooling fan in place.

The main issue is not how to tighten the cooling fan afterwards but how to open the flask to access the hall sensors and change them.

[Bikemad]

To remove the side cover, undo the nine allen bolts holding the side cover in place and place a piece of tape on the cover in line with the valve to make sure it goes back in the same position.

Place a block of wood against the end of the axle on the sprocket side and give it a nice firm tap with a large hammer or mallet to separate the cover from the hub. The joint is usually sealed with a silicone sealant, and it may require a fair bit of force (several large taps) to break the bond between the cover and the hub assembly.

Once the bond has been broken, the side cover should slide off the axle with a bit of persistent pulling and wiggling on the cover.

Check out this thread for more information.

Alan