Technical

At the recent summer meet we found some really odd behaviour with one of the club's controllers. Initially we blamed locos, thinking their pcb's might be the cause, but by the time we had the third anomaly, we realised it was the controller and not the locos. The behaviour is as follows:

Short flicks in each direction are OK, but...

A long hold of the control lever results in the motor initially turning in the correct direction, but then immediately reversing and then stopping moving. The reversing movement is slightly more than the initial correct movement. The whole movement there and back is over in about a second. After that, the controller will make no further movements in that direction.

However, if you hold the control level over in the other direction, the motor initially turns correctly, then reverses back the way it came and then stops. Again, the controller attempts no further movement in that direction, but if you hold the lever the other way it moves and then reverses...and so on.... and so on. I have captured a short video which might help with the explanation, but you will have to watch carefully.....

Question: has anyone ever seen any behaviour like this before ?

For info, the controller is a very early one:

Date on back: wk 44 2003

Circuit board: rev 4

Programmable chip: ver 1.0

I can't see anything particularly wrong with the pcb. There's the wire mod, which presumably resulted in the rev 5 circuit board, which is in most controllers. See photos for the main controller pcb:

If you've seen anything like this behaviour or have any ideas, please add a comment. In the meantime I will try to look a little deeper.

Thanks,

David