Atlas GP40 decoder question

[montyvox]

Good morning everyone-

I have a puzzling problem, well at least I think I do.

I have an Atlas Master Series GP40 for Guilford.

I bought an NCE 8 pin decoder for it. The only problem is, is that there are only 6 holes on the board.

It came with a jumper already.

My questions are this:

1. Why are there only 6 pins for an 8 pin decoder?
2. Does the engine already have the decoder in it?

I am confused.

Thanks for the help-

Matt

[CIOR]

Matt,
Robert is right, you have a engine with a "DUAL MODE" decoder in it.
www.atlasrr.com/decoder.htm



This was Atlas's way to get you into DCC when they introduced the dual mode decoders in the GP40 engines! They have been redone a few times, but the principle is simple.
The 6 pin plug you see is actual to switch from DC to DCC mode. So all you do is pull the pin and place it in the other holes to go from DC to DCC. Simple as pie, no need for another decoder.

I know I had a fleet of these decoders when they first came about, as I had about 10 GP40's and a few GP38's....

[montyvox]

Thanks men, you are the best!

I guess it couldn't be any easier than that, now could it.

Thanks again-
Matt

[montyvox]

Hello again-

So I get home last night, change the jumper from DC to DCC mode.

As soon as I put it on the tracks, I get this weird sound. And then, just like the real thing, white smoke starts coming out.

So it looks like the decoder is fried.

So I need to return it back to my LHS.

[CIOR]

Oct 22, 2009 8:07:38 GMT -5 montyvox said:

Hello again-

So I get home last night, change the jumper from DC to DCC mode.

As soon as I put it on the tracks, I get this weird sound. And then, just like the real thing, white smoke starts coming out.

So it looks like the decoder is fried.

So I need to return it back to my LHS.

Yes, and when you get the new one, read the directions on setting the plug.

I've got many of them and never had smoke from any of them.
Dunno what the deal was.

Also, always verify you have good connections and no shorting too (just nature of the beast). Sometimes its shotty workmanship from China!

[montyvox]

Thanks Matt.

I've been running other decoded stuff before now and this happened imediately as I put the engine on the rail.

I also tested it in DC mode and it did nothing. I'm guess crap workmanship from China.

[montyvox]

Right Robert.

I've seen this GP40 in person before, and I literally knew it would smoke quite a bit, but I didn't figure the model would do the same thing!

It must be a Guilford/Pan Am thing I guess.

[dtinut]

You might also want to test the decoder, by placing the loco on the programming track, instead of directly onto the regular pwered track, as this usually doesn't have the same power output.

Might keep ya from letting the smoke out - next time!

Brian

[montyvox]

Thanks for all the help guys.

I took the GP40 to my favorite hobby shop where I bought the engine, and my friend put it on his test track, and after a while, it began to look like an 0-4-0! The smoke was really getting bad.

So he replaced the decoder and it runs like it should, which is good.

Now I have yet another problem- I have a Shinohara/Walthers non-DCC ready curved turnout that is acting up.

When it's set in position, everything runs well. When I switch it, it creates a short and everything dies.

Is this the case where I have to add a "jumper" to the frog, since it's not insulated?

Thanks
Matt

[montyvox]

Thanks Robert-

So in other words, I need to cut into the back of the frog as to stop the flow of electricity from the points, correct?

I'm assuming I can do with with a dremmel tool and a cutting wheel, correct?

Thanks again-
Matt

[montyvox]

Thanks Robert!!

I get it now- and that makes a lot of sense.

So basically I am isolating the frog, and the two jumpers are going to provide power to it.

Sounds easy enough.

Thanks again-
Matt

[CIOR]

Ironic, as I've got a few older Shino C70 turnouts that are like this. I've got them all setup and just need to get the gaps cut in.

I've actually stopped cutting the forward (point end) portion of the rail, on these turnouts I use the blue point turnout controls and I feed power via the electrical contacts on the bluepoint.
This helps further prevent electrical issues of the dead frog. Since I will use 44 and 70 Tonners!

Just something to think about if you have that option, otherwise follow Robert's suggestion!