[Howzatt]

Just had an interesting experience chipping my nice new Bachmann 45xx Small Prairie.
Fitted the chip which was a doddle as there is plenty of room, removed the caps, tested and after running a couple of feet, l was unable to change speed of loco, it stuck at original set speed. Tried in reverse with same result. In one instance, it even changed direction on it's own! I tried other locos, all worked fine. I then disabled analogue DC in CV29, still no change. After much head scratching, I thought that spikes must have been corrupting the DCC signal. I decided to refit suppression caps to loco, tested, ran like a dream. This definitely goes against the well-tested "remove capacitor" logic, but I'm happy

, it works. I'm using an MRC Prodigy Advance system, which I am very pleased with, also TCS M1 and T1 decoders, which I find very easy to set up.

Has anyone had experience of runaway locos? Comments very welcome.

Best regards

 

[Howzatt]

Thanks for the replies everyone, I think I've read somewhere a theory that decoders should take care of any voltage spikes that suppression caps normally soak up. Size for size, how any component on a tiny decoder board can do this same job beats me. Perhaps I am thinking too "analogue" here.