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Bachmann D5233 Class 25

3680 Views 7 Replies 4 Participants Last post by  dwb
Hi all.
I'm thinking of getting the Two Tone Green Bachmann Class 25 (D5233), however I have read that the simple 1 fuction decoder supplied is hardwired onto the PCB. Would I therefore be able to cut the connections from the PCB to the decoder and solder in connections from a new decoder, or would this not work?

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I think it would be easiest to just remove the existing pc board altogether. Then attach your new decoder to the four wires remaining.
Hmmmm, aren't decoders 8 wires?
And isnt the PCB needed?!
4 important wires: 2 for the track connections (red and black) and 2 to connect to the motor (orange and grey). The rest are function circuits (lights etc.).
Decoders may have 9 or even more wires, but as Doug says for basic control only 4 are used. This particular model doesn't have lights fitted as far as I know, so there are just the motor and track connections to worry about.
Thanks for that guys, sorry to sound like a newbie and all, but if I did want to add functions later (or change the decoder) would I be able to do so or am I stuck with the bachmann decoder. Does anyone actually have this loco split from the digital freight set? If so anyone got any pics of it without the bodyshell on?
Ok, so the decoder is embedded in the PCB, what does this PCB *actually* do? Non-DCC trains seem to be missing this, is this just what makes the loco DCC ready? If so I presume i can do away with the PCB and plant in a decoder to it as if it was a standard non-dcc ready loco?
>what does this PCB *actually* do?
At a guess it directs the power from the rails into the decoder and connects the output from the decoder to the motor. That's apart from providing a steady state DC voltage for powering the decoder chip itself with maybe a few capacitors as well.

It makes sense for a manufacturer who is providing a "DCC on board" locomotive to do it this way. On the production line they just drop the PCB into the slot made specially for it, hook up the wires from the wheels and the wires to the motor and they're done. No need to pay extra for the 8 pin NMRA connector plug.

Of course this arrangement is not good for those who want to fit their own decoder, since they have to chuck the PCB and hope that the space left behind matches the decoder of their choice. They also have to make their own connections. For popular models fitted with a PCB, the after market decoder manufacturers will often make an indentical PCB which plugs instead. So far this is restricted to American models and some Kato units.

I hope this gives you some background

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