cart won't run

[JohnnieB]

Originally Posted by georgia088

Cool! Learning something new all the time! So, just curious.
1. How do you know the functional diagram for the alltrax is the same as the Curtis minus those couple of changes? Can you tell from the alltrax schematic? Or, do you have to physically test what is happening on the outside to be able to illustrate a functional diagram?

2. Oh and also, the v”s (and inverted v’s) in the functional diagram, are they just connection points? What are their meaning?

1. It is called "Reverse Engineering", or at least something akin to it. Except for the throttle input Analog) and the output (PWM), the control circuits of series and sepex controllers are digital circuits (Either have 0V or pack voltage), so a truth table (Boolean Algebra) can be made by observing what has to be true to get what output. Then figure out what has to be inside the black box to produce a specific output when a specific input occurs.

With a stock PDS controller, a direction has to be selected on the F/R switch to get the solenoid to click when pedal is pushed and with an XCT it will click when F/R is in Neutral.

The original drawing showing the voltage paths through a PDS controller was very likely made by someone that had opened a Curtis 1206MX and done some circuit tracing on the boards, or someone that had an actual schematic or wiring diagram for it, which are next to impossible to obtain.

2. They are the male and female pins in the plugs and jacks.

[georgia088]

Originally Posted by JohnnieB

1. It is called "Reverse Engineering", or at least something akin to it. Except for the throttle input Analog) and the output (PWM), the control circuits of series and sepex controllers are digital circuits (Either have 0V or pack voltage), so a truth table (Boolean Algebra) can be made by observing what has to be true to get what output. Then figure out what has to be inside the black box to produce a specific output when a specific input occurs.

With a stock PDS controller, a direction has to be selected on the F/R switch to get the solenoid to click when pedal is pushed and with an XCT it will click when F/R is in Neutral.

The original drawing showing the voltage paths through a PDS controller was very likely made by someone that had opened a Curtis 1206MX and done some circuit tracing on the boards, or someone that had an actual schematic or wiring diagram for it, which are next to impossible to obtain.

2. They are the male and female pins in the plugs and jacks.

Interesting!

[boandbabs]

Update, I did find a bad splice and the wire was separated inside the spiral wrap where it has been spliced before. I found another raw spot on both these wires also. Just got a chance to look today late. I will make splice and hopefully it goes back to working. I need to get some wire and splices. I will keep you updated.

[boandbabs]

Thanks again, I got the the bad wire repaired and it is running again. Thanks for all the professional help.

[JohnnieB]

Originally Posted by boandbabs

Thanks again, I got the the bad wire repaired and it is running again. Thanks for all the professional help.

Glad to hear you got it fixed...

[georgia088]

I’m just glad you listened to johnnieb and kg and not me!
Although, I will say my original controller was the same as yours. And it failed in the same way that we thought yours may have (controller not delivering b- to solenoid for activation). If I still had that controller or if I had it to do all over again I would find a way to activate the solenoid without the controller telling it to, and see how long it lasted.
Mine failed bc I shorted a wrench on two posts on the battery pack and it killed the activation function (may have killed more) idk. I didn’t know anything about them at the time (still don’t know much). So, I just got a new controller. I believe (and may be wrong) that the controller still had a lot of life left in it.... but guess I’ll never know.


I’m glad yours was a much cheaper fix than mine!

[georgia088]

JB: (or anyone who knows) You know I am full of questions.....

Why in the world would they make the pds carts in a way that the controller is necessary to activate the solenoid? It seems this is a high failure item, and the controller could other wise be perfectly fine. Is there some reason they didn't design them like the series carts where it was only the micro switches that activated the solenoid? Seems to me it is much cheaper to fix a microswitch that goes bad than the entire speed controller simply because of this feature.

I'm sure there is a reason, but I just don't understand it.

[JohnnieB]

Originally Posted by georgia088

JB: (or anyone who knows) You know I am full of questions.....

Why in the world would they make the pds carts in a way that the controller is necessary to activate the solenoid? It seems this is a high failure item, and the controller could other wise be perfectly fine. Is there some reason they didn't design them like the series carts where it was only the micro switches that activated the solenoid? Seems to me it is much cheaper to fix a microswitch that goes bad than the entire speed controller simply because of this feature.

I'm sure there is a reason, but I just don't understand it.

EZGO added a Walkaway Safety feature which limits the cart to about 2MPH so you can catch up with it and beeps rapidly to attract your attention if the cart starts rolling with the pedal up.

To do that, the controller has to supply B+ to the solenoid coil as well as B-. For issues like you mentioned and others, they re-designed the way the solenoid coil got B+ in the TXT-48, which has B+ supplied externally during normal operation and by the controller during Walkaway Safety operation.

The attached TXT-48 schematic shows the two B+ sources for the solenoid coil as well as showing the voltage inputs to the F/R switch, Keyswitch and pedal switch are all in parallel and external to the controller, eliminating the control voltage issues common with the PDS.

The Walkaway Safety is why sepex drives must be switched from Run to Tow when cart is Towed. Otherwise the heat produced by the strong regen braking trying to limit cart to 2MPH can burn up the motor and controller.

[georgia088]

Originally Posted by JohnnieB

EZGO added a Walkaway Safety feature which limits the cart to about 2MPH so you can catch up with it and beeps rapidly to attract your attention if the cart starts rolling with the pedal up.

To do that, the controller has to supply B+ to the solenoid coil as well as B-. For issues like you mentioned and others, they re-designed the way the solenoid coil got B+ in the TXT-48, which has B+ supplied externally during normal operation and by the controller during Walkaway Safety operation.

The attached TXT-48 schematic shows the two B+ sources for the solenoid coil as well as showing the voltage inputs to the F/R switch, Keyswitch and pedal switch are all in parallel and external to the controller, eliminating the control voltage issues common with the PDS.

The Walkaway Safety is why sepex drives must be switched from Run to Tow when cart is Towed. Otherwise the heat produced by the strong regen braking trying to limit cart to 2MPH can burn up the motor and controller.

Nice explanation as usual. So, with the txt48 is the controller responsible for changing the blue wire going to the solenoid to (-)?

[JohnnieB]

Originally Posted by georgia088

Nice explanation as usual. So, with the txt48 is the controller responsible for changing the blue wire going to the solenoid to (-)?

Yes, the blue wire (B-) is controlled by the controller, which closes the solenoid when the pedal is pushed. Probably so the controller will know when solenoid contacts are supposed to be closed for better error reporting.

Newer aftermarket series controllers also control the B- wire to the solenoid.