Fitting DCC sound chip & speaker to Bachmann 37

[Taxzilla]

Hi all.

 

I've been modelling for a while but wanting to take next step and fit sound to a loco.

 

I'll be getting a Bachmann class 37 shortly and I've already bought a Zimo MX644D decoder with stayalive capacitor and a Zimo 3D speaker.

 

I'm confident in fitting the chip to the loco but I'm not sure how/where to attach the capacitor, and also unsure of where to solder the wires to connect the speaker. Also not sure on exactly what type of wire to use.

 

If anyone could be of help it would be greatly appreciated - I could just take it to my local model shop (The signal Box, in Anstey, Leicester) but I'd love to be able to learn how to do this for myself.

 

Cheers!

[Phil Bullock]

If thats a current one it should have speaker connection points on the PCB - probably labelled SP+ and SP-

 

As for the wire - nothing too hefty needed, A fine multi stranded cpooer wire will be fine

 

Phil

[Izzy]

This guide is very useful  -  http://www.youchoos.co.uk/Index-Detail.php?L1=Detail&Item=MX644

 

You do need to attach the stay-alve wires before fitting the decoder as they are on the side that faces the PCB.

 

There should be pads on the loco PCB for the speaker wires somewhere. No doubt someone with a 37 will be along with the info/pics to help you.

 

Izzy

[Taxzilla]

If thats a current one it should have speaker connection points on the PCB - probably labelled SP+ and SP-

 

As for the wire - nothing too hefty needed, A fine multi stranded cpooer wire will be fine

 

Phil

Thanks for that Phil - much appreciated!

 

It is a current model (MMRG Ltd edition) so I'll look out for those. After wiring speak to the PCB points on the loco I assume its just a case of attaching the capacitor directly to the chip and I'm good to go. Are you able to help with where the wires should be attached to the speaker? (see picture)

 

Cheers, David.

[Taxzilla]

This guide is very useful  -  http://www.youchoos.co.uk/Index-Detail.php?L1=Detail&Item=MX644

 

You do need to attach the stay-alve wires before fitting the decoder as they are on the side that faces the PCB.

 

There should be pads on the loco PCB for the speaker wires somewhere. No doubt someone with a 37 will be along with the info/pics to help you.

 

Izzy

Thanks Izzy - that's really useful

 

Cheers, David.

[Izzy]

 

They are nice speakers. I have used them in a J15 and 08. The wires are attached to the spring contacts on either side. I always solder them on. Doesn’t matter which way around the wires go, but as you can see from the YouChoos help/guide it’s absolutely crucial with the stay-alive ones or it all goes pop/bang - along with all you’ve spent!

 

Izzy

[Izzy]

Meant to add, just in case you aren’t aware, do use a 25v capacitor, it’s the minimum voltage the MX644D’s circuit can use, unlike the MX645D ( which can use 16v). Usually Zimo/Rail Exclusive provide the correct voltage with the sample cap they give. If you use 16v then you must add the standard resistor/diode circuit as per normal.

 

Izzy

Edited September 3, 2018 by Izzy