70Views6Replies

Author Options:

NEED help understanding Circuit board & Wires ? Answered

i have 2 Mobility scooters with similar circuit boards , one has 3 more items connected thru the circuit board where as the other one has those 3 items in the fiberglass body on the tiller . One has the Ignition wires as B+(SW) and B+ as the ignition wires on the bigger circuit board , And the other has B+(SW) but no makings on the circuit board that says B+ ( but it does have B- ) , Both scooters have Curtis Motor Controllers 1203A,

But it says in the Curtis 1208C manual that The B+(andB-, if applicable ) wires supply power to the throttle control panel ----such as for the key switch ---- should be bundled with the remaining throttle wires so that all these wires are routed together .i've enclosed some pics and hope some one can help ..

Below are some pics describing the 2 Circuit board set ups for the same scooters hope some one can enlighten an old brain (that's slowly fading )

Kindest Regards in advance

Gordon

Tags:help

Discussions

0
Downunder35m
Downunder35m

22 days ago

Not sure if I can provide a lightbulb moment here...
There is no obvious question in your topic.
I just assume you have these scooters in parts and try to figure out how to cennted it all to make it work again?

0
GordonP9
GordonP9

Reply 18 days ago

the question i need answered is the B+ and B- on the circuit boards.... as seen on the bigger circuit board there is a B+(SW) & B+ on the larger pcb that lead to the ignition , but on the smaller pcb there is no B+ although there is a B- , how come there is no B+ on the smaller pcb ????
hope this makes sense i have no problems with the motor controllers at all

FRF9TW5H7W4T8ZW.jpg2x circuit boards colored wires.JPGwalkabout scoot colored dots.JPG
0
GordonP9
GordonP9

Reply 20 days ago

Hi thanks for your reply , my question is if the wiring from the loom start to finish is the same for both scooters the only difference being early model has the smaller pcb and the more modern one has the bigger pcb as the light switch, forward /reverse switch are attached to it , both have the 1203A control motor but that is not a problem my question is why would one board have a B+ on the circuit board and not the smaller one as it has a B- ,
i put some more pics on the pcb's there has to be a reason why both ignitions are wired through the circuit boards and yet there is no B+ on the smaller board ... Hope this makes sense
Kind Regards and thanks in advance for your help in the first place
Gordon

0
GordonP9
GordonP9

20 days ago

The circuit board pictures show that the ignition wires are from the B+( SW ) and B+ , the question i'm asking is the Smaller circuit board was the original type where the lights forward /Reverse switch , Light switch etc were in the actual body of the scooter where as the later circuit board has them in the actual circuit board , i'm just trying to find out why the smaller board does not have a B+ but it has a B- ?

Curtis Control pcb 1201A.JPGS6300160.JPGUntitled-1 clear board.jpgwalk about ignition.JPG1234.jpgcart 1.JPG
0
Downunder35m
Downunder35m

Reply 19 days ago

Had to drag my old and rusty scooter out to take a look on how things are organised there.
Mine uses a different system but I think I found enough similarities to compare.
The big board uses a relay and I simply guess this is causing your headache.
Once scooter switches all power on by just the switch alone, while the other goes a slightly safer route by having the ignitin switch only turn on the relay on the circuit board - this relay then powers up the rest of the system.
Have a look at your parts to see if this would make any sense, if not then I have to go back to the drawing board to figued out what the B+ problem is.

0
Jack A Lopez
Jack A Lopez

Reply 19 days ago

Here is a guess: The smaller circuit board does not have a node for B+, because the designer choose not to put one there.

If you are wondering where node B+ is located, my guess is it is on the key-switch. Moreover there are exactly two nodes on the key-switch: B+ and B+(SW). Those two nodes get connected together when the switch in the key-switch is closed.

Also if you are further wondering about B+, is it connected to the high side of the battery? The answer is "Not directly." It goes through a relay first. That is what it looks like to me, when I look at that circuit diagram in the first picture.

Moreover, I am guessing that relay sort of turns everything off; i.e. disconnects B+ from the battery, while the battery is being charged. I mean, it looks like the coil of that relay is connected to a funny circular connector symbol, labeled "CHARGE."

The rest of the time, when not being charged, and relay is not energized, I expect B+ is connected, or should be connected, to the high side of the battery, like the name "B+" suggests.

Obviously you are in a better position than me, to find what is connected to what, since you have the actual circuits, and you can put your ohmmeter on them for to discover these things.

0
Jack A Lopez
Jack A Lopez

21 days ago

So you have two scooters, both with Curtis 1203A motor controllers.

You know, it might help if we had a manual for that 1203A motor controller, or even a picture of it.

Maybe you thought the motor controller was so common that you did not need to take a picture of that part, presumably because everyone knows what that part looks like...

I think this page,

https://www.curtisinstruments.com/products/motor-c...

is the official manufacturer of these controllers.

If I scroll down on that page, a lot, I see sort of a list of different motor controllers, with a picture on the left, and a model number plus links (manual, datasheet, etc) or the right.

I see a 1204M and a 1205M, and those are the most numerically close to your "1203A."

I cannot compare by picture, because I have no idea what the "1203A" looks like.

One thing all of these motor controllers seem to have in common, is a group of fat, high current connectors (usually 4 of them, {B+, B-, M+, M-}, for the battery and motor), and a group of smaller, low current connectors(for control inputs and outputs).

For these Curtis controllers, the low current connectors often include a connection (3 pins) for a 5K potentiometer, for commanding the motor speed. I do not know if all of them work this way, but that just seems to be something common to the manuals I have looked at so far, which are 1208C, and 1204M and 1205M, which have the same manual, uh.. this one:

https://cdn.curtisinstruments.com/products/manuals...

It might would be worth your trouble to contact someone at Curtis,

https://www.curtisinstruments.com/contact/

https://www.curtisamericas.com/en/contact/

and ask if anyone has a manual, or any other documents, for this "1203A" motor controller.

Once you have someone's email there, presumably you could send a picture of this artifact to that someone. I mean, I am thinking you might have to, in the case where he or she denies the existence of this thing.

Also if you feel up to it, you could edit this topic, and attach that picture of the 1203A controller, here to this topic.

I am not promising that anyone here will actually be able to help you figure out that controller, once we have a picture of it, but it might help.