Zimo MX645 Decoder in LGB Otto

R

rgsmg53

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I have just installed my first sound decoder. I thought I would start simple and put it into a LGB Otto out of a starter set. Everything went to plan and mostly it tested out OK.

However, my one issue is that the front light will only illuminate when the loco is going in reverse! I have connected the blue and white wires as per the instructions and not the yellow wire which is supposed to be for the rear light. The light is a grain of wheat bulb and not an LED and is connected simply by two wires.

I'm in the process of searching to see if there is a CV which will swap the operation of the front and rear lights before I de-solder the white wire and try the yellow.

I originally did think that perhaps the polarity of the command station connection with the track would make a difference but soon dismissed this having thought about it! I have also taken care not to cross the Right and Left Rail connections (red and black wires) and, as the Otto is so simple, I very confident this is not the case.

As I'm new to this, I very willing to believe I may have done something stupid but the sound works a treat and exactly how it should do.

Any advice gratefully received.

Thanks,

Richard
 
Does your throttle show the Otto traveling in the correct direction? It sounds like you have crossed the motor wires over. You can change CV 29 to reverse direction but it's better to re solder the wires.
Cheers Colin
 
Can you actually see that the blue/ white wires are from the front lamp. Otherwise, as Colin suggests, is the loco going in the correct direction. What command station are you using for your DCC?
 
I'm using the Piko system.

The Navigator shows the correct direction of travel on its screen so I had assumed that meant that I had the Right Rail and Left Rail wired up the correct way round. Are there any other indications to check whether I have left and right the wrong way round?

Daft I know, but I also turned the loco to face the other way on my test track and of course the same thing happens and, fortunately, the Navigator still shows the correct direction of travel.

R
 
The ledt/right rail makes no difference on DCC. The suggestion is to swap over the motor feed wires from the decoder. But this will reverse the direction of travel. Easier to swap the rear/front lighting wires over.
 
Oh, and to answer Alan's question - yes, I removed the entire front lamp run (surprisingly easy to do) and it is merely three inches of black twin core cable terminating in a double socket for the bulb terminals. I did wonder if there was a diode in there but, if there was and the lamp lit in the wrong direction, it would mean that the lamp was on in both directions of travel. which I do not think is the default setting - I guess I'd better check the all the lamp CVs if I can find them.

R
 
Sorry, I didn't read Colin's reply properly. I am as confident that the Left and Right motor wires are correct as am for the Rails! This because there is a simple 4-way plastic plug between body wiring and chassis. I took the motor cover off to check the position of the motor connections. As supplied (ie for analogue operation) pins 1 & 2 and 3 & 4 are connected as two pairs. I have re-soldered the plug to give four separate connections.

Correct me if I am wrong, but if the motor wires were swapped then would not the Navigator show the incorrect direction of travel?

R
 
Yes it would. The motor seems to be wired correctly. But maybe not the lights. Id you can trace the lighting wires, swap these between front and rear.
 
Your motor block connections for an Otto should (when viewed from the cab side looking forward) black, grey, orange, red.
Blue and white are the correct connections for the front light.
 
rgsmg53 said:
I'm in the process of searching to see if there is a CV which will swap the operation of the front and rear lights before I de-solder the white wire and try the yellow.
Click to expand...

Hi Richard,

You should not need to rewire anything, as you suggest there should be a CV or two that will reverse the direction that the front light works in. I am no expert with Zimo decoders but I would be very surprised if Zimo did not have this feature. Try looking for 'Function Mapping', Massoth use the term 'Switching Output Commands'.

EDIT: I just found a ZIMO manual on the net. I think you need to change CV33 (and possible CV34 if you have a rear light). The manual says CV33 should contain 1 by default, try changing it to 2. (Change CV 34 from 2 to 1 for the rear light).
 
Motor block connections checked OK.

Front lamp wiring checked all the way and OK. There was no rear lamp on this loco - just a footplate lamp which I removed before fitting the decoder.

I guess I'll have to swap white and yellow wires. The only thing I can think of is that white and yellow wires were crossed during manufacture. I'll check the position of the white and yellow wires on the PCB.

Thanks for all your suggestions.
R
 
This is for Massoth. Your Zimo may well be the same.
CV51 controls the front light. The default is 128 which is switching 'on' in standard driving direction.
the value 64 is reverse only.
(unlikely, but if you use an F key {1 - 16} for switching lights you need to add the number of that F key to 128. On massoth there is a separate light key - this needs no additional addressing)
 
Does the light work correctly in the forward direction if you run the loco on analogue DC (with the decoder fitted)?

CV29 bit 0 reverses the direction of travel. In some decoders if you set this bit it doesn't swap the operation of the front and rear headlight functions (in other decoders it does). It's worth remembering that LGB actually uses the opposite rail polarity to the small scales, so in some cases CV29 bit 0 is set on to get round this.

One thing I always try and do when fitting a decoder is to make sure the loco still continues to run in the same direction under analogue DC as it did before the decoder was fitted. Then check it goes forward under DCC when instructed to do so. Once you've got that sorted by connecting the pickups and motor feeds to the decoder in the correct configuration, and maybe using CV29 bit 0 if you have to, then worry about the headlights. If they work the wrong way, I usually just swap the yellow and white wires at the decoder rather than fiddle with lighting CVs.
 
CV 51 on a Zimo decoder controls the signal approach brake influence ie the amount to brake for each signal colour.
Adjusting CVs on advanced decoders pays dividends but it pays to have a manual and make a note of those CVs you have changed in case you need to reset the decoder at any time due to human error.
Ask me how I know :)
 
I've always wanted to do this ...... ..... ... How do you know, me Lad?
 
Thanks to Cliff and a long time studying the Zimo manual I have changed CVs 33 & 34 as Cliff suggested. This has solved the problem so I'm not going re-solder anything.

I still need to think carefully about the decoder's default values but this is probably academic as I now know how to swap the 'front lamp' over.

Regards,

Richard
 
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