'86 Medalist 6 passenger won't run EZ GO type

Harolds secret weapon

okay, guys, i need some help with this one. I have already posted once or twice on a dillemma or two that i'm having with this cart, but got past those problems and can't figure this one out? I have 36 volts at my foot pedal switch, all my terminals on my Solidstate speed control device, on my solenoid, and my key switch. I even have 36 volts on the terminal at the top of my speed control, but i have nothing at my switch on the back of my FandR switch and nothing to the speed control from potentiometer which is located at acc. pedal. From the wiring diagram, or schematic it looks to be a pretty closed circuit, meaning, you close the FandR swith to say forward, and the contacts close sending the signal to the Speedcontrol telling it that it needs to move in the Fwd direction, but i have nothing on the + terminal of the speed control, so, i guess what i'm trying to find out, is where does the voltage come from that feeds the FandR switch, potentiometer so that circuit will work? Does it come from the top +(36Volt) terminal? if so, i have voltage there, it looks like it might be my speed control device then?
Thanks guys, sorry this is so long, wanted to be as specific as possible to help with troubleshooting

BGW

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JohnnieB

You are mixing and mingling three separate circuits. They interact with each other but they have separate functions and each is more or less standalone.

The controller limits the amount of current the motor can draw.
The throttle potentiometer tells the controller how far to turn on
The F/R switch determines which way the current flows through the Stator windings of the motor.

Here is a drawing showing the controller and F/R switch in clearer layout than what you see on the schematic.
As you see, there is a single current path from the positive terminal on the battery pack through the solenoid contacts, through the F/R switch, through the Stator windings and through the Armature and back to the main negative terminal on the battery pack.

The only difference in the high current loop between forward and reverse, is the direction of current flow through the stator windings.
Every cable, connection and contact used in forward is also used in reverse.

The voltage for the throttle potentiometer is a regulated voltage supplied by the controller. Something in the 10 to 15V range.

The first step is to get the solenoid to click. If the solenoid contacts are not clicking closed, voltage readings at the controller, F/R switch and motor are more or less meaningless.

If the solenoid contacts are closing, connect your DVM between the B- and M- terminals on the controller.
You should read full battery pack voltage when throttle pedal is press just far enough for the solenoid to click.
If you don't have it, leave the negative test lead on the b- terminal and trace the high current loop back towards the main positive terminal of the battery pack.
There will be an open somewhere along the way.

Attached Images

Hi Current Circuit - Series Motor - EDITED.JPG (63.6 KB, 0 views)

Harolds secret weapon

Thank You for the response Johnnie B..I will check it all out and get back to you, also the schematic/drawing should help too..Thanks again

Harolds secret weapon

Okay, Johnnie B. I checked that out what you had posted last about checking B- and M- on the controller and my solenoid clicks. Just to give you a bit of an idea again, where i'm showing voltage and not. I have 36 Volts to microswitch footpedal, 36 volts on everywhere my solenoid needs voltage to operate, 36 volts on my controller, and battery voltage on my batteries, but I'm not getting battery voltage on my FandR switch on any post and from the key switch I have 36 volts, but once it leaves there, i dont have anything on the ohter side of reverse switch of FandR switch? I'm thinking its my little microswitch that is probably the problem, but wanted another opinion first, or someplace else i should check first..also, I have 36 volts to top and middle small terminals on my speed control. Soooo, the only thing i can think of is I need to find a way to get power to my fwd reverse switches to get power to my potentiometer right?
this one is a screwy one....

JohnnieB

The idea you are giving me is still the same one I originally had, but was too polite to comment on, so let's just say that the points where voltage measurements have been taken appear to have been selected randomly, the theory of operation being applied is flawed and the resulting conclusions are less than accurate.

IF the solenoid is clicking AND you do not have battery pack voltage between the B- and M- terminals on the controller, the problem is in the heavy gauge cables or what those cables connect to.

Gonkulor

Take a breath friend. Back up a bit. Take a step back and go to the top of this thread and start over with Johnnies first recommended action. Remember we all are helping each other here on our own time. JohnnieB is the class act to figure out what you have wrong. Don't be afraid to re-ask a question or ask for an explanation of what/why something he is asking you to do

If you don't have all the tools to answer those questions we will help you to get those tools.

Harolds secret weapon

I hope nobody took anything i was trying to say the wrong way..I wasn't trying to sound short or rude. If I did, i apologize. I sat down and figured out where i have and don't have voltage, and right now it looks like my FandR switch is bad, or could be the problem. I really appreciate all the help!!
and again, if somebody thought i was answering or commenting with any attitude or anything, i didn't mean to. Thanks for all the help to everybody!!

JohnnieB

Sorry I came down so hard.
My morning coffee probably hadn't kicked in yet.

Given the cart's age and that it can haul 6 Passengers, you'll probably want to go with a Heavy Duty F/R like one of these.
http://www.cartsunlimited.net/F_R_Switch_Upgrades.html
I think you will have to call to get the right one for your cart.

Harolds secret weapon

Thank You sir. I'll check it out. Yeah, we got to have our coffee..
Again I greatly appreciate the help!
i'll give you a hollar if anything else pops up..
thanks again

scottyb

HSW, nice of you to apologize but, as Johnnie said, there is no need. Lots of people come here and tell us stuff about their carts we can't use in our analysts.
You are not the first one to try to be helpful in such a way.
Each of us have certain preferred ways to test.
And sometimes yes, keyboard techs get frustrated LOL