DCX 300 Amp Controller No LED

[gunnardog]

Originally Posted by JohnnieB

Voltage to Pins 9 & 10 comes from the Run/Tow switch.
Voltage to Pin-6 comes from the keyswitch, via the F/R switch.
With voltage on Pins 6, 9 & 10, the LED should blink a number of times (Indicating what the throttle type setting is. 4 blinks = ITS) and then stay on steady green.

At this point, the controller is powered up and applying pack voltage to Pin-5 (Pressing the pedal) will tell the controller to connect Pin-7 to B-, which energizes the solenoid.

The voltages needed to power-up the controller (Green LED on) appear to be there, but the controller is not turning on. This points to the controller being bad, but I'd do some more checking before declaring it bad.

Instead of connecting the DVM's negative test lead to the main negative terminal on the battery pack, connect it to the B- terminal on the controller and recheck the voltages on Pins 6, 9 & 10. If they still have pack voltage on them, the controller is not powering up when it is being told to do so.

I suspect the reason no voltage was measured on Pin-5 is because the pedal was not pushed at the time. However, Pin-5 is not needed to turn the controller on, it just tells it to activate the solenoid after the controller is turned on.

Also, when measuring the voltages, slightly lift the 10-pin connector on top of the DCX and measure on the actual pins themselves.

Yes you are right, I didn't check pin 5 with the accelerator depressed. I will do the checks as you outlined and then get back with the results. Thanks for the good directions, even someone slow like me can follow them!! Haha.

[JohnnieB]

Originally Posted by gunnardog

Yes you are right, I didn't check pin 5 with the accelerator depressed. I will do the checks as you outlined and then get back with the results. Thanks for the good directions, even someone slow like me can follow them!! Haha.

I used to teach troubleshooting at Sheppard AFB.

[scottyb]

Originally Posted by JohnnieB

I used to teach troubleshooting at Sheppard AFB.

You must have been the 1st instructor on the base.

[JohnnieB]

Originally Posted by scottyb

You must have been the 1st instructor on the base.

Not quite, but when I say I'm old school, I do mean old school.

When I started studying electronics, everything used vacuum tubes, including computers, and transistors barely existed outside R&D labs. It has been a long and meandering road, but I have thoroughly enjoyed witnessing the evolution of technology while learning new stuff, and sometimes relearning old stuff, as I traveled it.

Ironically, the ancient troubleshooting process I learned as a child and taught as an adult, is still being taught today. The technology has changed, but the process hasn't.