I think I fried my Magic Pie II internal controller while trying to test halls

[Pwd]

So I finally got around to popping the side cover off of my Magic Pie to inspect the hall sensors...

http://i.imgur.com/I6dXKYk.jpg

I applied power to the positive and negative directly on the board and then noticed a flame that came from this resistor on the controller! (I cut the power and unplugged right away):

http://i.imgur.com/ovKR0vf.jpg

Did I do something wrong? Is this controller definitely fried now? Any advice appreciated

[Morgen 3Eman]

How many volts did you apply where?  Smoke from components is a sure sign of damage.

Have you picked a replacement yet?

TTFN,
Dennis

[Bikemad]

I have just been studying a couple of controllers to try and determine what the resistor is for, but it's impossible for me to trace the circuitry.

This it what it should look like:



If I've interpreted the colour code corrrectly, the resistor seems to be a 51 Ohm resistor with a 5% tolerance.

One of the controllers I was looking at was the one I blew up when I tried a dual controller modification, and I discovered that the resistor had been nicely cooked on that one as well:



I would say that something on the controller has short circuited and caused the resistor to blow, and when my controller blew it managed to kill all three hall sensors at the same time!

I think you will have to replace the controller with another internal one, if you can still get them, or you may need to convert the motor to allow the use of an external controller if you can't find a replacement internal one.

Alan
 

[Pwd]

Hello

I applied 54V to the large red and black (battery wires) wires where they are soldered onto the board. That is the connections on the board to the left in the first picture. That was just to give power to the controller. My thought was that once the controller had power, it would be supplying +5V to the hall sensors and I could proceed with testing them. It was a terrible smell, with a bit of flame too

This controller was already replaced last year and GM Canada doesn't seem to stock the MP2 internal controller any more. So if I can't repair this one, I may be looking at a new setup for my front wheel.
 

How many volts did you apply where?  Smoke from components is a sure sign of damage.

Have you picked a replacement yet?

TTFN,
Dennis

[Pwd]

I can't seem to get the images you posted  to work ... but thank you for the reply. Do you think it is worth attempting to replace the resistor? It sure would be nice to just spend a few bucks on a resistor.

I have just been studying a couple of controllers to try and determine what the resistor is for, but it's impossible for me to trace the circuitry.

This it what it should look like:



If I've interpreted the colour code corrrectly, the resistor seems to be a 51 Ohm resistor with a 5% tolerance.

One of the controllers I was looking at was the one I blew up when I tried a dual controller modification, and I discovered that the resistor had been nicely cooked on that one as well:



I would say that something on the controller has short circuited and caused the resistor to blow, and when my controller blew it managed to kill all three hall sensors at the same time!

I think you will have to replace the controller with another internal one, if you can still get them, or you may need to convert the motor to allow the use of an external controller if you can't find a replacement internal one.

Alan

[Morgen 3Eman]

I want to tell you that I have never seen a schematic for a GM circuit board……

But,

 My guess (based on 40? 50? years of electronic troubleshooting) is that the resistor is for dropping voltage to the 5vdc? analog voltage regulator.  Here is my thought train…..  Your photo shows a 470 MFD 63 Volt rated electrolytic capacitor in physical proximity to a high wattage resistor.    It is a fairly common design to have a filter cap with the voltage dropping resistor in an analog regulator circuit.  Electrolytic caps are notorius for failing under voltage stress near their rating.  By near their rating, I  mean avoid stressing them over 75% of their rating.  i.e., nothing over 45VDC for a 63V rated cap.  54 VDC is way to high a voltage to put across a 63 V cap, in my opinion. 

So, if you want to try replacing the resistor, by all means you should try it. I would suggest taking the cap out of circuit, and testing it for failure as well. 

Good luck

TTFN,
Dennis

[Pwd]

Thanks for the replies

I'm going to throw some more questions here:

What is poor practice applying the battery voltage directly to the board instead of the cable end?
Is it ok to apply power with the hub separated from the wheel?
What size resistor would that 51 Ohm one be? 1/2 Watt?

Thanks again

[Bikemad]

My guess (based on 40? 50? years of electronic troubleshooting) is that the resistor is for dropping voltage to the 5vdc? analog voltage regulator.

If that is so, why does it have to be such a precise resistance (51 Ohm with 5% tolerance) considering there is such a large variation in the battery voltage (24 to 48V)?

What is poor practice applying the battery voltage directly to the board instead of the cable end?
Is it ok to apply power with the hub separated from the wheel?
What size resistor would that 51 Ohm one be? 1/2 Watt?

I don't know about poor practice, but I find it a lot easier to connect the battery to the power lead to leave both hands free and also to reduce the possibility of getting it wrong.

I have powered up stators while separated from the wheel and the only problem I noticed was a hall sensor error on the controller because there were no magnets in close proximity of any of the three hall sensors.

It could be a 1/2 watt resistor as it is larger than 1/4 watt resistors, but a lot smaller than a 2 watt resistor which seem to be twice as long and twice as thick.

Alan
 

[Morgen 3Eman]

Hi Folks,

I did mention it was a guess…Show me the schematic to change my mind. Since you are asking "Why?", why did GM,  who designed the schematic, knowiinlgy subject a 63 V rated cap to anything near 60V?   

Anyway,  maybe a Lyen controller will fit in that space if a GM replacment is not available.   

TTFN,
Dennis

[Pwd]

Hello again

So I just ordered some resistors FYI I think its a 51ohm resistor (they only had 2%). Same physical size as some 1/2W resistors I had lying around. I have my older internal controller still and had a look at it.... I'm hoping thats all that is blown. Here is a better shot:

What is poor practice applying the battery voltage directly to the board instead of the cable end?
Is it ok to apply power with the hub separated from the wheel?
What size resistor would that 51 Ohm one be? 1/2 Watt?

I don't know about poor practice, but I find it a lot easier to connect the battery to the power lead to leave both hands free and also to reduce the possibility of getting it wrong.

I have powered up stators while separated from the wheel and the only problem I noticed was a hall sensor error on the controller because there were no magnets in close proximity of any of the three hall sensors.

It could be a 1/2 watt resistor as it is larger than 1/4 watt resistors, but a lot smaller than a 2 watt resistor which seem to be twice as long and twice as thick.

Alan
 

Thanks for the input, I wasn't just being lazy and didn't want to pull the power harness off my bike to give me access to the power leads. If I just wave some magnets (ones from an old hard drive), would that switch the halls for me? 

Hi Folks,
I did mention it was a guess…Show me the schematic to change my mind. Since you are asking "Why?", why did GM,  who designed the schematic, knowiinlgy subject a 63 V rated cap to anything near 60V?   
Anyway,  maybe a Lyen controller will fit in that space if a GM replacment is not available.   

TTFN,
Dennis

Now you've got my gears spinning  ... are there other mini/internal controllers that would fit inside? That would be awesome to have a more reliable (and more powerful) internal controller. I like the internal controller for the front application. I've already got a rat's nest of wires haha:
http://i.imgur.com/KbVVEj9h.jpg

[Pwd]

Just an update... I received the resistors and replaced the one on the board but the new resistor suffered the same fate. It too has burnt out once I applied battery power to the controller. I think the time has come to retire this MP2.

Now for my next questions:

Is it possible to remove the core from my rear MP2 and use it as a front motor or is the axle position different?

If I bought just the external control Magic Pie motor without a wheel, would it fit in my wheel that was being used with the internal controller? This would save me trying to re-lace the new motor into the wheel, I could just pop the cover off, put it in the wheel and put the cover back on. Would that make sense?

Thanks again fellas

[Pwd]

I may have just found the answer about turning a rear pie into a front pie:

http://goldenmotor.com/SMF/index.php?topic=335.msg11854#msg11854

It looks like although swapping right side covers would work, the axel on a rear pie may not be threaded far enough back to the center to fit in a front dropout. Can anyone confirm this?

[GM Canada]

Placing the external controller inside the MP2 housing won't work unless you do some magic with opening the controller itself and put it inside with out the controller housing. Still with the shape not designed right and no mount or hook ups it would be a challenge to say the least.

You are correct about the side cover difference and the thread not being threaded far enough. The rear axle accommodates a 135 mm width. The front 100 mm. You would either have to machine the thread down further or open the front forks 35 mm.

With spring finally in the air I'm thinking a new build. I'll likely be stripping a kit from one of my bikes and redoing it with the latest and greatest of products. Drop me an email if you want to pick up something used.

Gary

[Pwd]

Thanks Gary. Email sent.