I got a GP-40 in a bachmann train set and I was wanting to add Dcc to it. How do you add a decoder to it and where do I get one for it? I also have a Dcc version of the exact same GP-40 but the number on the side is 3507 instead of 3500.
You can get a decoder from your local hobby shop, an online dealer or ebay.
By the way the pc board that is already in it has what looks like 8 holes along the board to like put something on it so does that mean all I need to do is just buy the decoder and just set it on there or are the holes there just for the heck of it?
the bachmann gp40 is not a split frame locomotive, so the directions acy referenced don't apply. the 8 pin socket you mentioned sounds like a standard dcc socket. if it is, there should have been a plug inserted into it for dc use. if this is the case, any decoder with as 8 pin plug should work. i for one am glad to hear of the upgrade to the board. one of my current projects is dcc in a bachmann b23-7, which is a similar design to the gp40. it's taken me a while to figure out exactly how to install a decoder in that one.
the holes are along the edges of the circut board and i got the GP-40 in a Bachmann Rail King train set