Dapol Terrier with Zimo MX644D

[skip37216]

My Dapol Terrier runs fine on analogue straight out of the box.

But with a Zimo MX644D (21 pin)  installed  I have a mysterious problem.  In reverse only it runs and then stops for maybe 2 to 4 seconds then starts off again only to stop again after a short while and so on. When the loco stops the background sounds continue and the firebox still glows so it is not a pickup problem.

In forward direction it works perfectly. I have tested the decoder separately on my ESU test rig and it performs faultlessly. I have tested the loco on 12 volt analogue with and without the chip fitted and again it is perfect.

This defies any logic - I do not perceive any mechanical problems - the decoder works on the ESU test rig and the loco runs fine with the decoder fitted on DC.  I am missing something but do not know what else I can check.

I thought there could be contact between the underside of the decoder and the loco wiring board but I inserted a slip of paper between and eliminated that as a possibility. I have double checked the wiring between the board and the motor.

I have tried it on 14, 27,28 and 128 speeds steps just to eliminate a possibility.

I have fitted the default capacitor that comes with the decoder but have not tested without this.

 

Any sensible suggestions will be appreciated?

[pauliebanger]

My Dapol Terrier runs fine on analogue straight out of the box.

But with a Zimo MX644D (21 pin)  installed  I have a mysterious problem.  In reverse only it runs and then stops for maybe 2 to 4 seconds then starts off again only to stop again after a short while and so on. When the loco stops the background sounds continue and the firebox still glows so it is not a pickup problem.

In forward direction it works perfectly. I have tested the decoder separately on my ESU test rig and it performs faultlessly. I have tested the loco on 12 volt analogue with and without the chip fitted and again it is perfect.

This defies any logic - I do not perceive any mechanical problems - the decoder works on the ESU test rig and the loco runs fine with the decoder fitted on DC.  I am missing something but do not know what else I can check.

I thought there could be contact between the underside of the decoder and the loco wiring board but I inserted a slip of paper between and eliminated that as a possibility. I have double checked the wiring between the board and the motor.

I have tried it on 14, 27,28 and 128 speeds steps just to eliminate a possibility.

I have fitted the default capacitor that comes with the decoder but have not tested without this.

 

Any sensible suggestions will be appreciated?

 

Depends. Where did you get your decoder and sound project from?. Not all ZIMO sound projects are created equal. 

 

This is one of those curious effects where neither the decoder nor the loco are in any way faulty, but put them together and strange things happen.

[skip37216]

Hello Paul

From a good source - Digitrains.

Are you suggesting that somehow there can be a combination of decoder and loco that will exhibit  a fault?

[pauliebanger]

Hello Paul

From a good source - Digitrains.

Are you suggesting that somehow there can be a combination of decoder and loco that will exhibit  a fault?

 

Digitrains, that is a good source. Lol

 

Yes, I am. Mine exhibited the same issues, though the reason could be different. 

 

Sorry to have to ask another question, but which F key operates the Firebox Glow effect?

 

Kind regards,

 

Paul

[skip37216]

Hi Paul

I don't go along with fantasy and there must be a logical explanation for the fault I am experiencing.  It's hardly rocket science or some secret witch doctory effect.

As for the F key I don't see the relevance but the firebox is on F13 and its also on random - very effective using two LEDs

 

I would very much appreciate any sensible suggestions to investigate - it's driving me nuts!

[pauliebanger]

Hi Paul

I don't go along with fantasy and there must be a logical explanation for the fault I am experiencing.  It's hardly rocket science or some secret witch doctory effect.

As for the F key I don't see the relevance but the firebox is on F13 and its also on random - very effective using two LEDs

 

I would very much appreciate any sensible suggestions to investigate - it's driving me nuts!

 

Not sure where the fantasy reference comes from, I'm trying to help you.

 

The relevance of that question is that it will help me to ascertain which version of the sound project you have.

 

Summing up the facts; The loco runs fine on DC, so it's reasonable to assume the loco motion is mechanically OK.  The decoder runs fine on the ESU tester,so there's no obvious fault here.

 

You have made physical checks on the loco and the DCC connector and not found a problem.

 

Despite this, when the decoder is fitted to the loco you experience intermittant stalling whilst the sound remains on, so power is getting to the decoder and poor contacts, dirty track etc are therefore not causing the stalling.

 

The only cause I could think of was that the decoder was becoming overheated and it was shutting down power to the motor. When it cooled sufficiently, the power to the motor resumed until it overheated again and so on.

 

If that's the case, the areas to investigate are;

 

Does the decoder get excessively hot? Too hot to hold a finger against it, that is?

 

You may have tried this, but you haven't said. Does the problem occur if operated with the sound is turned off? Does it happen when the firebox flicker is not operating?

 

In my case, I was unable to check these last two separately as F key 1 started the sound and the firebox flicker simultaneously. I reassigned Function Output 1 to another key to investigate, and the problem disappeared.

 

The question still remains, what caused the overheating? (In my model). I don't know.

 

It appeared to me that with the firebox flicker on 'permanently' the problem was evident, but with it used intermittantly, ie triggered by the random sound, things work fine.

 

Just a thought. Have you turned the sound up? If so, try setting the default value for this project, CV266 = 50.

 

Kind regards,

 

Paul

[Ray H]

Is it worth testing without the capacitor? Is the capacitor confirmed as being the right way round - I assume it is polarised?

[pauliebanger]

Having slept on this (the problem, not the loco) I remembered that there is a 'bolt-on' RF suppressor added between the decoder and motor terminals. (It's actually soldered, of course). It is situated below the main PCB with the 21 pin connector and just 'floats' on a scrap of insulation. There are bare connections close to the edge of this mini PCB. Could this be moved when the motor is reversed, creating a short?

 

Suppressors are not normally required with decoder equipped models. If my earlier suggestions do not help, you could try removing this and wiring direct to the motor from the relevant solder pads on the main PCB. ZIMO decoders aren't often upset by RF supressors, but I've known the odd model to cause problems, maybe this is another.

 

Inany event, I plan to remove the one in my model when I have a minute or two.

 

Kind regards,

 

Paul

[skip37216]

Hi Paul

There must be a logical explanation - that's what I mean by not fantasy.

I've just spoken with Digitrains and they suggested removing the suppressors so I'll give that a go and let you know if that has any effect.

To answer the other possibilities:

There is no overheating - the decoder remains cold.

Switching the sound off and switching the fireglow off has no effect.

I turned the sound down to 20 and that had no effect.

[pauliebanger]

Hi Paul

There must be a logical explanation - that's what I mean by not fantasy.

I've just spoken with Digitrains and they suggested removing the suppressors so I'll give that a go and let you know if that has any effect.

To answer the other possibilities:

There is no overheating - the decoder remains cold.

Switching the sound off and switching the fireglow off has no effect.

I turned the sound down to 20 and that had no effect.

 

Who do you think Digitrains asked? Lol

 

In the meantime, I've taken the one out in my model and it now works perfectly. Seems the other issues were red herrings.

 

I've also just  received  an official response from my friend at ZIMO that this is the most likely cause of the issue we have observed, and confirming that the decoder provides better suppression than chokes and capacitors so it's OK to remove them.

 

I think this will solve the problem for you.

 

Kind regards,

 

Paul

[skip37216]

Hi Paul

I have just removed the small suppressor board which is located (lodged) underneath the main DCC socket board. A tad on the Heath Robinson side, Dapol are relying on the wires keeping this board in place and it obviously did not quite do the job.

Now that I have removed the resistor board she works perfectly.  I just wired the motor directly to the DCC board eliminating the suppressors a very neat solution.

There must have been some transient effect maybe which killed the power to the motor.

 

Thanks for your help.

[oxfordjub46]

i too have this problem with the Dapol o gauge terrier ie suddenly stops but a few seconds later starts again and so on in either direction, i have two of these locos and the problem persists with both of them ( maybe i am just unlucky) i have sent one of them back to the suppliers for them hopefully to rectify the problem and it looks like i will have to do the same with the other one unless anybody out there has any suggestions, it is such a shame as for the price they are really nice looking locos but i am very dissapointed with the performance

[charliepetty]

i too have this problem with the Dapol o gauge terrier ie suddenly stops but a few seconds later starts again and so on in either direction, i have two of these locos and the problem persists with both of them ( maybe i am just unlucky) i have sent one of them back to the suppliers for them hopefully to rectify the problem and it looks like i will have to do the same with the other one unless anybody out there has any suggestions, it is such a shame as for the price they are really nice looking locos but i am very dissapointed with the performance

Has anyone told Dapol.  And Asked them for a solution, as they might not know!!!  Charlie

[skip37216]

Has anyone told Dapol.  And Asked them for a solution, as they might not know!!!  Charlie

Hi I reported the problem and had a response so I'm sure Dapol will resolve the issue on later production..

Rather than send the loco back it's easy to just remove the suppressor board and the problem is no more

[pauliebanger]

Has anyone told Dapol.  And Asked them for a solution, as they might not know!!!  Charlie

 

Hi Charlie,

 

Yes, Dapol were informed as soon as I discovered the issue.

 

Dapol are fitting ZIMO MX644D decoders in their R-T-R sound fitted models, so it's important they sort this issue out, especially at the premium they are charging over the non-sound fitted models.

 

Kind regards,

 

Paul

[pauliebanger]

To Anyone suffering from poor running with Sound fitted Terriers.

 

These are really nice models so it's a pity that they have been fitted with a 'last minute' fix which has not been properly tested, even with the sound decoder they intended to fit.

 

I have highlighted this issue in my Terrier review in Hornby Magazine issue 101.

 

In next month's HM, issue 102, in the Staff Projects section a 'Step by Step Guide' to fitting sound in the Dapol Terrier I show how to remove the suppressor which will solve the problem.

 

Of course, with a new loco supplied as sound fitted, you have the option of returning it for repair to the dealer who supplied it to you. They should also meet all postage costs as this is a manufacturing/design fault.

 

Kind regards,

 

Paul

[MarcD]

Only problem I have had with my terrier is it has a tendency to run on if running a speeds greater than 7. Ran it on my old shunting layout at Keighley show once I got use to the running on at speed it worked first time. Though the volume was loud at home but when I was at the show you could hardly hear it.

 

Marc  

[pauliebanger]

Only problem I have had with my terrier is it has a tendency to run on if running a speeds greater than 7. Ran it on my old shunting layout at Keighley show once I got use to the running on at speed it worked first time. Though the volume was loud at home but when I was at the show you could hardly hear it.

 

Marc  

 

Marc,

 

Is this a Dapol R-T-R sound-fitted model or have you fitted an aftermarket decoder?

 

I suspect the running on you describe is due to the momentum setting in CV4. Are you running on DC or DCC? If DCC is that 7 out of 28 speeds steps or 7 out of 128 speed steps?

 

There are a number of ways to increase volume, try increasing the value in CV266. Ther's a lot more free air for the speaker to excite in a show venue than a small room at home.

 

KInd regards,

 

Paul

[MarcD]

Thanks for the tip.

 

I fitted the decoder myself. I will have a go at CV4  and CV266 tomorrow when the wife has gone off to work and I cant get any complaints. As for the steps i'm not sure as I have never had the need to go past 14. I'm using a Lenz 100 system if that's a clue.

 

The room was very open but the US logging layout that was next to us was very loud.

 

Marc

[pauliebanger]

Marc,

 

CV 266 for volume only applies to ZIMO decoders.

 

What value do you have in CV29?

 

Paul

[brossard]

Can I join in and bump this thread?

 

I just installed sound in my Terrier (Zimo MX644D w/ Pauls Sound Project and a Zimo 3D speaker).

 

I don't get sound and while it runs, it buzzes a lot and is not smooth.

 

It came from Hattons with one of their decoders installed and ran very nicely.

 

Here's a pic of my installation:

 

 

I assume the spare pads on the right of the board are for the speaker.  These are connected to the pink and blue wire.

 

Stay alive is connected to the decoder as can be seen and polarity is correct.

 

There was mention of suppression and I suppose that the small board does that.  I need to get rid of these I suspect, do I just cut the wires?

 

Any ideas of what my sound issue could be?

 

I should add that I've done this job many times, on my 08, Jinty, Railbus (groan!) and FSB J50.

 

John

 

Edit:  Having another look around I found yet another board under the decoder board.  This getting to be like an episode of UXB.  This has green doobies and is connected to the other small board. 

 

 

Which wire do I cut sarge? (sweat dripping off nose and hands shaking)

 

Edit 2:  I have checked the connection from the decoder pins to the pads with a multimeter - these are good.

 

Edit 3:  Just double checked my soundfile and it is ZS019 by Tony Molyneux.  Sorry Paul.

Edited January 14, 2018 by brossard

[Ray H]

Is that pink & blue wires that you've fitted, or the ones that are part of the wiring harness as supplied?

[brossard]

I added the pink and blue wires myself Ray.

 

John

[Ray H]

Interestingly the decoder manual doesn't seem to show where the speaker wires should be attached.

 

In fact as far as I can see it implies that the speaker wires should be attached to the board on the loco into which the decoder is plugged in (or I may need to go to SpecSavers!).

[brossard]

See Edit 2 Ray, the spare pads are for the speaker connection.

 

John