DCC Installing a Zimo MX 696s decoder with Ribbon Cable

Discussion in 'Techniques' started by richard carr, 29 December 2019.

  1. richard carr

    richard carr Western Thunderer

    I bought one of these a few months ago and when it turned up with ribbon cable as the connection method I was a bit puzzled as to what to do so it sat there for quite a while doing nothing.
    Now this is my 4th install of the MX696, the ribbon cable works really well so here are the details of how I have done it.

    The MX696 is one of the large scale Zimo decoders, it is rated for 4amps continuous current and 10 amps peak ! It has 8 function outputs giving up to 2 amps current in total and has a 10 watt amplifier for the sound. It should more than cope with a Heljan loco and has enough sound for a really big speaker.
    It does not have a built in stay alive but has the support circuitry to accept capacitors.

    Here's the decoder with the ribbon cable.


    It is 69mm by 29mm by 18mm high, you can snap off the ends to make it only 55mm long if need, i'll be doing this to get it into a Heljan 25.

    The ribbon cable gets gently clamped in the connectors you can see at the top of this photo and then you squeeze it all together in a vice and you now have 10 connections in one connector and 20 in the other.

    Here it is the vice ready tobe forced together


    You can see 5 sets of teeth here and behind that is another set of 5.


    And here it is all squashed together. These now plug into the decoder and you solder the loco wires tothe ribbon cable.

    Here's the decoder with the 20 way connector fitted to the decoder

  2. richard carr

    richard carr Western Thunderer

    That is probably the trickiest bit done, you now have 30 wires connected to the decoder and it takes 5 minutes to do it.

    So the first thing with any install is to test the decoder. Most of the major manufactures have their own dedicated decoder tester, this is the Zimo one.


    For the smaller decoders one tester will cover all the different plug types but for larger decoders you often need the dedicated one, you do here the MX696 just plugs in and you can connect it to your dcc system to test, but use the programming track connections to reduce any riskof damaging it.
    Dud decoders do get sent out, I have had 3 over the years, if it doesn't work it is a lot easier to send it back now in pristine condition rather when you have started fitting it.

    Here's the decoder plugged in to the tester, I then connect it to decoder pro via the SPROG and if all is well do the initial programming like setting the number and swiss mapping for the lights, speed tables and things like that.

    This one was all ok on test so now its time to install it.

    It is going inside a Heljan 25/3, to remove the body there are 4 screw in the chassis hidden by the rear of the bogies, but moving the bogie to one side allows you to remove the screws mine came out easily.
    Boyblunder likes this.
  3. richard carr

    richard carr Western Thunderer

    This is the inside of the 25, the wires are all nicely colour coded for once and the PCB tells you what each one is.



    The roof fan has its on small PCB ideally you want to retain this and power it from one of the ordinary function outputs, this gives the fan a nice slow speed.


    The deacode light and cab light, yellow wire for the rear one.

    The model uses two horizontal motors connected to gearboxes by a universal joint to power the loco.

    There isn't as much room inside the body as you might imagine, so I found it necessary to put the decoder and the speaker on top of the gearboxes.
    The decoder will not fit on top of the motors.


    With the cable the length supplied is more than enough but don't be tempted to cut it too short.

    I have added some plywood support for both the decoder and the speaker. The speaker is a Tang Bang, the smallest one they do, but they only seem to be available from Parts Express in the US.


    There are a lot of wires with the ribbon cable so make sure you count carefully so that you are connecting up the right ones. I use 1.5mm and 2mm shrink wrap to insulate all the joints.

    The decoder doesn't have an in built stay alive so I'm using a TCS KA3


    This will keep things running for 30 seconds after losing power.
    The other thing you can see in this image is the roll of Black Tack, this is a super sticky version of blue tack and I use it to fix everything in place, the decoder the speaker and the plywood supports are all held in place by it, I think its really good. I got mine from You Choos, but I'm sure you can get elsewhere too.

    The only other thing to add is that if you are going to use a lot of Zimo decoders, you really need to use Decoder Pro to do the programming, it's free you just need ti buy something that connects your computer to the track and generates the DCC commands. I use a SPROG 3 as its cheap and gives over an amp of current more than enough to programme and drive anything.
    It is worth getting to understand Swiss mapping as this allows you to easily map any function key to the function output you want to use with it.

    This is the screen in decoder pro I have set Function key F0 to be the front and rear lights and then used F17 to be the tail lights as that is what is connected to function outputs FO6 and FO2, function key F18 is for the roof fan, this is connected to function output FO4.