Positive Earth and Modern Electrics

tomspro · May 27, 2015

I just purchased a Gmax helmet with an LED in the back that can be triggered remotely by the MC brake circuit.
Of course, they assume negative ground for the sender unit, as do all modern electronics.

Hate to blow the thing up so...
what is the general rule for connecting to our beloved Norton with positive earth?
- hook up per instructions
- reverse the connections
- forget about it because will not work

lrutt · May 27, 2015

Just isolate it from the frame and hook positives to positives and negatives to negatives. As long as it doesn't touch the frame or something i'd think it would be ok.

tomspro · May 27, 2015

lrutt said:
Just isolate it from the frame and hook positives to positives and negatives to negatives. As long as it doesn't touch the frame or something i'd think it would be ok.

will do!
thanks...

tomspro · Jul 1, 2015

Sorry to revive this old thread, but I just tried connecting this thing and it works - BACKWARDS.
Ignition on, unit thinks brake is engaged and lights up.
If I step on the brake, it turns off.
If I reverse the wire connections, nothing.
So is there any hope of a simple solution to 'reverse the signal reversal''?
(yes - i am the reverse of an electrical genius)

comnoz · Jul 1, 2015

tomspro said:
Sorry to revive this old thread, but I just tried connecting this thing and it works - BACKWARDS.
Ignition on, unit thinks brake is engaged and lights up.
If I step on the brake, it turns off.
If I reverse the wire connections, nothing.
So is there any hope of a simple solution to 'reverse the signal reversal''?
(yes - i am the reverse of an electrical genius)

Do you have the positive lead connected to the chassis and the negative lead connected to the brake light wire?

If you post the wiring instructions I could tell you more. Jim

L.A.B. · Jul 1, 2015

comnoz said:
tomspro said:

Sorry to revive this old thread, but I just tried connecting this thing and it works - BACKWARDS.
Ignition on, unit thinks brake is engaged and lights up.
If I step on the brake, it turns off.
If I reverse the wire connections, nothing.
So is there any hope of a simple solution to 'reverse the signal reversal''?
(yes - i am the reverse of an electrical genius)

Click to expand...

Do you have the positive lead connected to the chassis and the negative lead connected to the brake light wire?

If you post the wiring instructions I could tell you more. Jim

Gmax ?? (From 1:37)
[video]https://youtu.be/EHle_QozFZM[/video]

comnoz · Jul 1, 2015

L.A.B. said:
comnoz said:

tomspro said:

Sorry to revive this old thread, but I just tried connecting this thing and it works - BACKWARDS.
Ignition on, unit thinks brake is engaged and lights up.
If I step on the brake, it turns off.
If I reverse the wire connections, nothing.
So is there any hope of a simple solution to 'reverse the signal reversal''?
(yes - i am the reverse of an electrical genius)

Click to expand...

Do you have the positive lead connected to the chassis and the negative lead connected to the brake light wire?

If you post the wiring instructions I could tell you more. Jim

Click to expand...

Gmax ?? (From 1:37)
[video]https://youtu.be/EHle_QozFZM[/video]

OK, It's not going to work without a relay. If you want to go ahead I can draw up a schematic. Jim

tomspro · Jul 1, 2015

That video is for the RECEIVER in the helmet.
It has nothing to do with the TRANSMITTER unit which I am trying to get to function.
Below is an image of the instructions. Hope it is readable.

Seems like I only have three choices.
1. Yellow wire to Norton white . White wire to ground. Does not work at all.
3. White wire to Norton white. Yellow wire to ground. Works in reverse.
3. Send it back.

L.A.B. · Jul 1, 2015

tomspro said:
That video is for the RECEIVER in the helmet.
It has nothing to do with the TRANSMITTER unit which I am trying to get to function.

I suggest you watch the video again from 1:37 in?

tomspro · Jul 1, 2015

L.A.B. said:
[
I suggest you watch the video again from 1:37 in?

OK - they do show connecting transmitter.
But that is what I am doing and it is REVERSED functionality with my positive earth system.

comnoz · Jul 1, 2015

tomspro said:
L.A.B. said:

[
I suggest you watch the video again from 1:37 in?

Click to expand...

OK - they do show connecting transmitter.
But that is what I am doing and it is REVERSED functionality with my positive earth system.

Positive earth has nothing to do with it.
It is built for a lamp that has power applied all the time and grounds one side of the filament to turn on the light as most modern bikes do. jim

tomspro · Jul 1, 2015

well i guess i will just have to live with my electrical incompetence and the fact that this is not working as intended.

isolated MC wire that activates brake light.
connected transmitter unit to it.
step on brake - brake light on, transmitter light off.
release brake - brake light off, transmitter light on.

on to more important things. thought this might be a universal positive earth problem.

comnoz · Jul 1, 2015

Do you have 3 wires going to your tailight socket.

One should be brake light power

One should be tail/running light power.

The third would be chassis ground- usually red -but sometimes its not there and the socket just relies on the mounting to ground the shell of the bulb.

Make sure you are not connecting to the running light wire. Jim

Positive Earth and Modern Electrics

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lrutt

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L.A.B.

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