Desperate!! Help needed with Marathon cart for baseball team

eneal1024

I have a 1989 Marathon cart that we use for our baseball team to prepare the fields. One of the kids decided to do me a favor and wash the cart. Well, now it doesn't move. It is an older cart and lots of rusty parts but I have tried to troubleshoot what I can. It appears that someone has done an upgrade from resistor coils to solid state controller. On the back of my sweeper board are resistors connection each metal stud together.

Troubleshooting steps taken:
bench tested the motor = passed
full pack voltage is 38.2v
Power on front and back side of solenoid
Solenoid click when accelerator engaged
full pack voltage when testing M- and B- although voltage does not drop when pressing accelerator = Fail?
Tested voltage at each metal stud on sweeper board and I get voltage on each and progressively more as the accelerator is pushed further
FNR switch appears to send voltage to the correct place when moved

Cart still doesn't move and our season starts this week.

Please help if you can. I am mechanically inclined but don't know what to do here.

BGW

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scottyb

The most water sensitive part of this drive system is the throttle signal potentiometer. Second are the F&R micro switches. Micro switches are ok if the solenoid engages (clicks) when you try to go. SO-
Click = potentiometer signal device water logged. Use a leafblower then hair dryer on it.
No click. use hair dryer on F&R and potentiometer micro switches.

eneal1024

The cart has been sitting for at least 2 months now so I'm not sure that there is still water on the sweeper board. It doesn't have the fancy potentiometer.

Could the resistors in the picture be fried? Does anyone know what values I should get at each post if checking with a DVM?

IMG_1814.JPG

cgtech

If you go from the farthest ends, you should get a total close to 5000 ohms. The resistors individually could be 5x 1000 ohm each, or any similar combo totalling 5k ohm.

eneal1024

It looks like I have about 4600k when going from end to end.

Something weird that I just noticed is that as soon as I turn the key on the solenoid clicks even with no throttle. When I switch from forward to reverse it shuts off in the middle and then clicks again when it engages in reverse.

Could that be the cause of it not moving? It is a new solenoid.

One other note and I'm not sure if it is relevant or not but when checking the volts on the sweeper I progressively get more when I press the pedal as you would expect but it tops out at about 7.6 volts.

I'm trying everything here and getting very frustrated and my wife isn't making it any better with comments like "I have never seen you not be able to fix something"

Please help me recover my status with my wife.

eneal1024

I found a flaw in my wiring from the previous post. I fixed it and now the solenoid only clicks when the pedal is pushed.

Still no movement though.

When checking voltage at the controller it does not drop when the pedal is pushed further down like I read it was supposed to.

I am getting power to the cables on the back of the FNR a with if that help at all.

cgtech

Label & pull the wires off the motor. Do a ohm test on the "A" terminals, and the "S" terminals.

scottyb

Motor test? I thought it worked before it was washed, right?

cgtech

Oops! Right...

eneal1024

Motor was just bench tested again and I have continuity between motor posts.