Installing a Keep Alive in Bachmann S4 With sound

[Trainmaker]

Does Anyone know how to install a Keep Alive in a Bachmann S4 with sound?? I'd Appreciate any help.

[rich1998]

A keep alive has two wires. Positive and negative.
Look at the decoder board for the positive and negative points. Best point for many is at the output of the full wave bridge rectifier which consist of four diodes next to each other. Get out your Optivisor and ohm meter and trace out the circuit. The below link will show examples.
Some decoders have more diodes next to each other.
I have not looked at the decoder layout.

http://www.members.optusnet.com.au/mainnorth/alive.htm

I am sure someone will chime in since they know the decoder. Get i right the first time. You do not want reverse polarity on a keep alive. You don't.
Be advised, if running the loco on DC, you will have no control, even if you turn off the power pack but that is rare.

Rich

[Trainman203]

I don't know how, but if I'd  bought one, I would read the instructions several times and get done specific questions first.

[Trainmaker]

Thank You rich1998, The net address was 100% helpful! Thank You Too Trainman203, I'll make My question clearer next time.

[rich1998]

In case you have not soldered before, a fine point 40 watt soldering pencil for PC board work. I have no idea of your soldering experience. Just remember, electrolytic caps do not like reverse polarity.

Rich