Home Forums General Discussion Technical Questions Epoch 1 Problem

I'm having an intermittent issue with the KLD input signal that is on the T I/O Board. The signal intermittently goes low even though the 120 VDC is present on the T I/O board. I have swapped the T I/O board and the computer board with another car and the input still remains faulty. The only other thing I can think of is a bad back plane board but it seems unlikey because the input signal tends to fail only a few runs after powering up the controller. Would anyone have a schematic of the back plane board so I can trace the signals or does anybody have any other ideas that would point me in the right direction? Thanks.

Doesn't the signal also go through the filtering terminal on the front of the controller.Try using a pull up resistor to see if you can force the signal up...I would tend to think not a backplane problem. Most likely the filtering circuit is failing to do it's job.

I don't remember seeing a filter circuit on the front of the controller. I'll have to look into that. I have swapped the signal from kLU to KLD and the KLD input still failed unless your suggesting the filter circuit is loading the signal after it makes it to the I/O board. Not sure about that???

I really can't remember either. Above the board draw behind the cover is where all field wires are connected if memory serves me correctly. You may have a problem with that connection point..... I'll have to check a print tomorrow, it's been awhile..It's where you would pull high the car calls without the HHT. I think it goes through the filtering circuit before it gets to the IOT board?

try new MGI bd

I'll give that a try. Did you have a similar problem that pointed to the MGI board?

Yes .But actually any board in rack is a possibility - all share common data bus. However, MGI shares secondary backplane with IOT - look into drawer and you will see it. This is why MGI is likely suspect.

edge connector on top of board......?

Sorry, I forgot to respond on this one. Itsallgood, apparently your very good with your Epochs. It did end up being the MGI Board that was causing the problem, Good Call!! Unfortunately, we got that problem fixed and then found that the motor and generator were both grounded. The car is still down for these repairs.