1997 txt suspected bad controller

[Terry J]

Hey everyone, new member but I've been lurking and doing a lot of reading for a while now.

97 ezgo txt dcs, all of a sudden completely lost power. Batteries are good. Solenoid tests good, I have battery power at solenoid battery side and controller side when accelerator pressed. Voltage lower than spec when accelerator not pressed at 28v on controller side. I'm suspecting a bad resistor, but my understanding that would not cause the cart to not work, which leads me to think the controller has failed as well.
Performed controller input tests I found on here, all test good. Checked all wiring to motor for resistance and voltage drop.
Performed electric motor test per schematic using 12v source, wheels turn.

Voltage when checked between s1 to s2 as accelerator depressed jumps from 0v very quickly to 34v, and changes polarity with switch in reverse. Voltage between a1 and a2 starts at 0v and barely moves at all, staying under 0.1v as pedal depressed.

By my testing looks like I need a controller and a new resistor, but want to confirm before ordering.

Thanks for the help. And props to everyone who contributes on here and the site for all the great info and resources.

[JohnnieB]

The resistor should read about 250Ω.

The voltage on the solenoid's controller side large terminal typically reads about 3v to 5V less than whatever the battery pack voltage is at the time, so twice the normal voltage drop across the pre-charge resistor probably means the controller is drawing more milliamps in standby (about 20ma typical) than it normally does rather than the resistor being bad.

The filed voltage (S1 -> S2) responds to the throttle, but the armature voltage (A1 -> A2) doesn't, so the high power portion of the controller has gone belly up.

The stock DCS controller (Curtis 1206SX) is a faulty design, so replace it with an Alltrax XCT48400-DCS or larger and upgrade the solenoid to one with at least a 200A rating. The resistor might be okay.

[Terry J]

Thanks for the help, definitely referenced a lot of your other posts while troubleshooting this. Will have to put an order in for the recommended controller. Cheers.

[JohnnieB]

BTW: XCT controllers in EZGO sepex drives (DCS, PDS & TXT-48 ) have "Regen" diode between the solenoid's large terminals rather than a resistor.