OO gauge GWR Mogul and Prairie

[TheSignalEngineer]

18 minutes ago, 57xx said:

what does the black dot on the tender signify...?

Paint spot? Don't think it appears on the picture on Hattons website.

[57xx]

Just now, TheSignalEngineer said:

Paint spot? Don't think it appears on the picture on Hattons website.

 

Yup, my comment was very tongue in check. They have manage to get a very perfect circle with it though.

[melmerby]

1 hour ago, 57xx said:

 

Close-up of the up-hill slidebars.

 

Other than that it appears to be a very nice model. Hoping to dig out the test rollers or track later in the week to give it a run.

Those slide bars really IMHO deserve to be better.

Not only an unwanted taper but they are flared out as well.

Why is that such a let down? The rest of the model is a much higher standard.

[St Enodoc]

7 minutes ago, 57xx said:

 

Yup, my comment was very tongue in check. They have manage to get a very perfect circle with it though.

Perhaps it's the Black Spot (cf "Treasure Island")?

[Jon Harbour]

On 03/12/2020 at 16:23, Jon Harbour said:

 

Haven't heard anything to this effect.... I would expect Hattons and Rails to be al over this updating customers once verified... Hopefully it isn't the case.

 

I actually contacted Hatton's yesterday about this. They indicated that they had not heard anything of this nature and that the previous delays in the sound-fitted models was due to Dapol not having the decoders in country and that this issue had now been sorted. They did promise to check on the validity of the rumour concerning Dapol abandoning the sound-fitted models and get back to me.

[Neal Ball]

15 hours ago, checkrail said:

Thanks for the thought, but no.  It didn't light when I first tested it straight out of the box before I'd meddled with anything.

Forgive me for stating the obvious John.... have you tried F0 and added either foil or white paint on the back of the motor housing?

 

Its not that bright, to the point you gave to look direct into the firebox, but on mine it is there.... Good luck!

[boxbrownie]

12 hours ago, 57xx said:

 

Yup, my comment was very tongue in check. They have manage to get a very perfect circle with it though.

Obviously sneezed from quite a distance then.......

[Izzy]

13 hours ago, melmerby said:

Those slide bars really IMHO deserve to be better.

Not only an unwanted taper but they are flared out as well.

Why is that such a let down? The rest of the model is a much higher standard.

Is it me, or do the slide bars sit at an angle to the footplate, (quite apart from the being bent part), higher at the motion bracket than the cylinders... might be the basic cause of those odd few that don’t run too well.  Such a shame, looks quite good otherwise as the nicely weathered example by checkrail shows. 
 

Izzy

[Chuffer Davies]

18 minutes ago, Izzy said:

Is it me, or do the slide bars sit at an angle to the footplate, (quite apart from the being bent part), higher at the motion bracket than the cylinders... might be the basic cause of those odd few that don’t run too well.  Such a shame, looks quite good otherwise as the nicely weathered example by checkrail shows. 
 

Izzy

Hi,

the slidebars are a single casting that is a press fit into the rear of the cylinder.  It is possible that it was not pressed home correctly during assembly or, if the fit is loose and was knocked, it could move in the cylinder.  It should be straight forward to correct any alignment issues and if the fit is loose then a spot of glue will lock it in place.

 

Frank

[Gopher]

I have just installed a Zimo MX658N sound decoder and have encountered a world of pain.

The loco ran O.K on DC, but on DCC was very erratic.  It ran well for a few seconds but there was no inertia or coasting.  When you shut the throttle down the loco stopped dead.  I tried a CV8 reset a couple of times, with no improvement in running.  Then finally the loco ground to a halt,  my DCC  system had a fit and shut down due to a short circuit and there was a lovely smell of burning from the loco.   The decoder was also hot. 

 

I am not sure where the problem lies, but suspect it might be the circuit board in the loco.  I obtained the sound decoder from one of my usual suppliers, and know they test them before sending them to customers.

 

I removed the decoder from the loco, reinserted the blanking plug,  and the thing will not run on DC now.

 

Anyway - loco has now been replaced by my excellent model shop.  I think the decoder is also damaged so will need replacing.

 

So I am not sure if the loco damaged the decoder or vice versa.  Although I have never heard of a faulty decoder screwing up a loco, so I know where my suspicions lie.  I have tested the replacement loco with a non sound Dapol Next 18 decoder and it seems to run O.K.

 

Having said all that I think the loco is a lovely model.  Hopefully my experience is a one off, and it is possible the fault lay with the decoder.

 

Still peed off though.            

 

[boxbrownie]

3 hours ago, Chuffer Davies said:

Hi,

the slidebars are a single casting that is a press fit into the rear of the cylinder.  It is possible that it was not pressed home correctly during assembly or, if the fit is loose and was knocked, it could move in the cylinder.  It should be straight forward to correct any alignment issues and if the fit is loose then a spot of glue will lock it in place.

 

Frank

Better tell Dapol 

 

[Gopher]

2 hours ago, Gopher said:

I have just installed a Zimo MX658N sound decoder and have encountered a world of pain.

The loco ran O.K on DC, but on DCC was very erratic.  It ran well for a few seconds but there was no inertia or coasting.  When you shut the throttle down the loco stopped dead.  I tried a CV8 reset a couple of times, with no improvement in running.  Then finally the loco ground to a halt,  my DCC  system had a fit and shut down due to a short circuit and there was a lovely smell of burning from the loco.   The decoder was also hot. 

 

I am not sure where the problem lies, but suspect it might be the circuit board in the loco.  I obtained the sound decoder from one of my usual suppliers, and know they test them before sending them to customers.

 

I removed the decoder from the loco, reinserted the blanking plug,  and the thing will not run on DC now.

 

Anyway - loco has now been replaced by my excellent model shop.  I think the decoder is also damaged so will need replacing.

 

So I am not sure if the loco damaged the decoder or vice versa.  Although I have never heard of a faulty decoder screwing up a loco, so I know where my suspicions lie.  I have tested the replacement loco with a non sound Dapol Next 18 decoder and it seems to run O.K.

 

Having said all that I think the loco is a lovely model.  Hopefully my experience is a one off, and it is possible the fault lay with the decoder.

 

Still peed off though.            

 

Right another conundrum.  I have been running the replacement loco which was DCC  fitted with a Dapol DCC decoder pre fitted.  It does some strange things.  It runs well and very smoothly, but then on occasions if you change direction, the loco stalls, stutters - jerks backwards and forwards slightly, and continues to do so ignoring any subsequent commands from the controller.  What is really odd  - is this still happens when I  kill the power to the track - the loco continues to twitch back and for.  I am not sure if there is an on board capacitor which causes this. 

 

The loco runs quite happily on DC, and most of the time on DCC, it just has these occasional twitches on DCC which is a tad concerning.  I have to say the number of occasions with the twitching became less the longer I ran it.  The firebox led is definitely not working or it must be very very dim, cannot even be seen in the dark.  I think I may have to return it for hopefully another replacement.  

 

Conclusion is that there is some issue with the DCC connections on the circuit board (says a non expert).  This appears to be the second Dapol mogul I have had with DCC problems.  

 

Any other DCC users had any issues ? (I might also have to post this on the DCC thread)  

 

On a more positive note - it runs very smoothly over all my track work.  I have a couple of dodgy bits - points and crossovers which I have to take slowly with some of my steam locos.  The Mogul flies through these without a murmur, and is very sure footed.  If I can get my DCC problems sorted I will be a happy bunny.                

[melmerby]

1 hour ago, Gopher said:

  What is really odd  - is this still happens when I  kill the power to the track - the loco continues to twitch back and for.  I am not sure if there is an on board capacitor which causes this. 

 

 

Really?

If you kill the power the track, unless fitted with a stay alive (unlikely) the decoder will lose power in a small fraction of a second and the motor will stop, irrespective of any small capacitors used for suppression.

[Neal Ball]

1 hour ago, Gopher said:

Right another conundrum.  I have been running the replacement loco which was DCC  fitted with a Dapol DCC decoder pre fitted.  It does some strange things.  It runs well and very smoothly, but then on occasions if you change direction, the loco stalls, stutters - jerks backwards and forwards slightly, and continues to do so ignoring any subsequent commands from the controller.  What is really odd  - is this still happens when I  kill the power to the track - the loco continues to twitch back and for.  I am not sure if there is an on board capacitor which causes this. 

 

The loco runs quite happily on DC, and most of the time on DCC, it just has these occasional twitches on DCC which is a tad concerning.  I have to say the number of occasions with the twitching became less the longer I ran it.  The firebox led is definitely not working or it must be very very dim, cannot even be seen in the dark.  I think I may have to return it for hopefully another replacement.  

 

Conclusion is that there is some issue with the DCC connections on the circuit board (says a non expert).  This appears to be the second Dapol mogul I have had with DCC problems.  

 

Any other DCC users had any issues ? (I might also have to post this on the DCC thread)  

 

On a more positive note - it runs very smoothly over all my track work.  I have a couple of dodgy bits - points and crossovers which I have to take slowly with some of my steam locos.  The Mogul flies through these without a murmur, and is very sure footed.  If I can get my DCC problems sorted I will be a happy bunny.                

Sounds like a faulty decoder. I’ve had it before with a cheap decoder, threw it away and the loco was fine. (Quite a few years ago, not this Mogul)

[Harlequin]

1 hour ago, Gopher said:

Right another conundrum.  I have been running the replacement loco which was DCC  fitted with a Dapol DCC decoder pre fitted.  It does some strange things.  It runs well and very smoothly, but then on occasions if you change direction, the loco stalls, stutters - jerks backwards and forwards slightly, and continues to do so ignoring any subsequent commands from the controller.  What is really odd  - is this still happens when I  kill the power to the track - the loco continues to twitch back and for.  I am not sure if there is an on board capacitor which causes this. 

 

The loco runs quite happily on DC, and most of the time on DCC, it just has these occasional twitches on DCC which is a tad concerning.  I have to say the number of occasions with the twitching became less the longer I ran it.  The firebox led is definitely not working or it must be very very dim, cannot even be seen in the dark.  I think I may have to return it for hopefully another replacement.  

 

Conclusion is that there is some issue with the DCC connections on the circuit board (says a non expert).  This appears to be the second Dapol mogul I have had with DCC problems.  

 

Any other DCC users had any issues ? (I might also have to post this on the DCC thread)  

 

On a more positive note - it runs very smoothly over all my track work.  I have a couple of dodgy bits - points and crossovers which I have to take slowly with some of my steam locos.  The Mogul flies through these without a murmur, and is very sure footed.  If I can get my DCC problems sorted I will be a happy bunny.                

 

This all sounds very odd and to work out what's going on you need to eliminate some of the variables. What decoder are you using now? If you put the same decider in another loco does that loco behave the same? If you put a different decoder in the Mogul does it behave badly? Etc., etc...

 

The firebox light is very dim even when it's working properly. Are you using F0 to turn it on?

 

[Chuffer Davies]

10 hours ago, melmerby said:

Really?

If you kill the power the track, unless fitted with a stay alive (unlikely) the decoder will lose power in a small fraction of a second and the motor will stop, irrespective of any small capacitors used for suppression.

I agree.  When you ‘kill the power’ how are you achieving this?  Are you setting the controller to zero or are you disconnecting the wires from the track?  If the controller is still connected could the controller be leaking current?  If the latter then is there leakage from another power source? Have you put a  voltage meter across the track?  
Please let us know how you get on...

Frank

[Gopher]

11 hours ago, melmerby said:

Really?

If you kill the power the track, unless fitted with a stay alive (unlikely) the decoder will lose power in a small fraction of a second and the motor will stop, irrespective of any small capacitors used for suppression.

Yes - it is so weird.  The thing keeps moving.  I have never come across this before.  There is also a smell of something running hot - probably the decoder.

 

11 hours ago, Harlequin said:

This all sounds very odd and to work out what's going on you need to eliminate some of the variables. What decoder are you using now? If you put the same decider in another loco does that loco behave the same? If you put a different decoder in the Mogul does it behave badly? Etc., etc...

 

The firebox light is very dim even when it's working properly. Are you using F0 to turn it on?

The loco was pre-fitted with a Dapol imperium decoder.  Yes tried F0 for the firebox glow, the instructions state it should work off F1.  I am afraid I do not have another Next 18 decoder, or another Next 18 loco to  experiment with.  This morning, it developed another unwelcome habit.  This time if I put the loco in reverse and then shut the throttle down - it just keeps running.  If I cut power to the track it will stop.  It does not do this going forward.   As an aside - I use a Digitrax controller, and have a ZTC controller for my programming track.  The loco plays up with both controllers.   I have been using DCC for at least 10 years  and have quite a few DCC sound fitted locos, with a variety of chips.  Never come across this before.

 

56 minutes ago, Chuffer Davies said:

I agree.  When you ‘kill the power’ how are you achieving this?  Are you setting the controller to zero or are you disconnecting the wires from the track?  If the controller is still connected could the controller be leaking current?  If the latter then is there leakage from another power source? Have you put a  voltage meter across the track?  
Please let us know how you get on...

Frank

   I am using the Digitrax controller to kill power to the track.  This is after setting the controller to zero.  I don't think the controller is leaking current because any other DCC locos on the layout shut down instantaneously.  I have not used a voltage meter.  I think the issue is with the circuitry in the loco or possibly the chip.  It is so odd that this is the second loco with similar problems.  The last one damaged a Zimo decoder.  Logic might dictate that the issue must be my DCC set up.   However all other locos run perfectly.

 

Thanks all for your advice and comments.  I think I may return the loco, and see if it is third time lucky.        

[Harlequin]

Wierd...

Does anything look odd on the decoder or the carrier board?

 

[melmerby]

49 minutes ago, Gopher said:

  I have not used a voltage meter.

Have you got one?

If not I would recommend a digital multimeter, it might not give completely accurate reading of DCC voltage or current (due to the frequency and waveform) but is very good for comparison purposes.

https://www.screwfix.com/p/lap-mas830b-digital-multimeter-600v/75337#_=p

 

Or if you are feeling like splashing out a bit:

https://www.screwfix.com/p/kewtech-kt117-true-rms-digital-multimeter-600v/5205p

Which should measure DCC voltage correctly

 

When you "kill the power" the power should be disconnected from the track completely. i.e. there is no volts. Nothing.

When the DCC system is on there is the exactly same voltage on the track whether the controller is set to zero or maximum, only the embedded DCC signal changes,

 

If you still have any power on the track when the system is "off" the DCC system itself is faulty and needs servicing/replacing.

 

If there is no voltage on the track, unless the loco has stay alive, it will stop, very quickly, suppression capacitors alone should not be large enough to store any significant amounts of power.

 

Edited December 9, 2020 by melmerby

[Chuffer Davies]

1 hour ago, Gopher said:

 I am using the Digitrax controller to kill power to the track.  This is after setting the controller to zero.  I don't think the controller is leaking current because any other DCC locos on the layout shut down instantaneously.  I have not used a voltage meter.  I think the issue is with the circuitry in the loco or possibly the chip.  It is so odd that this is the second loco with similar problems.  The last one damaged a Zimo decoder.  Logic might dictate that the issue must be my DCC set up.   However all other locos run perfectly.

 

Thanks all for your advice and comments.  I think I may return the loco, and see if it is third time lucky.        

Just to be clear; with DCC there is a constant voltage to the track.  When your Digitrax controller says the loco’s speed is zero this is purely a code passing between the command station and the chip in the loco.  If the loco does not behave as expected this is a fault in the loco’s circuitry or chip.  I am starting to wonder if there is a problem in the alignment of the PCB in the socket in the loco that is causing leakage between the track feed and the motor feed? This would put the chip at significant risk of damage.  Have you tried reseating the PCB?  
Frank

[Chuffer Davies]

Also:  I’ve just checked and it is possible to insert the PCB upside down.  The top is marked on the PCB so worth checking you’ve got it the correct way round. I would predict that inserting it upside down could be fairly catastrophic.

Frank

[melmerby]

17 minutes ago, Chuffer Davies said:

Also:  I’ve just checked and it is possible to insert the PCB upside down.  The top is marked on the PCB so worth checking you’ve got it the correct way round. I would predict that inserting it upside down could be fairly catastrophic.

Frank

Now that is poor design, if it allows destructive voltages in the wrong places.

[57xx]

6 hours ago, Izzy said:

Is it me, or do the slide bars sit at an angle to the footplate

 

No it's not just you, I did mention it in my first post with the pics I think the whole cylinder block is sitting at an angle. I need to dig back as am sure someone else has posted in the thread about tweaking this.

[Gopher]

4 hours ago, Harlequin said:

Wierd...

Does anything look odd on the decoder or the carrier board?

Not as far as I can see.  I had a look at the decoder and the PCB, nothing obvious I'll get my magnifier to double check.  My feeling is the PCB is the problem in this loco and the original loco which screwed up the Zimo decoder. 

4 hours ago, melmerby said:

Have you got one?

If not I would recommend a digital multimeter, it might not give completely accurate reading of DCC voltage or current (due to the frequency and waveform) but is very good for comparison purposes.

https://www.screwfix.com/p/lap-mas830b-digital-multimeter-600v/75337#_=p

 

Or if you are feeling like splashing out a bit:

https://www.screwfix.com/p/kewtech-kt117-true-rms-digital-multimeter-600v/5205p

Which should measure DCC voltage correctly

 

When you "kill the power" the power should be disconnected from the track completely. i.e. there is no volts. Nothing.

When the DCC system is on there is the exactly same voltage on the track whether the controller is set to zero or maximum, only the embedded DCC signal changes,

 

If you still have any power on the track when the system is "off" the DCC system itself is faulty and needs servicing/replacing.

 

If there is no voltage on the track, unless the loco has stay alive, it will stop, very quickly, suppression capacitors alone should not be large enough to store any significant amounts of power.

Thanks for this.   I am pretty certain the track is dead when I kill the power on the Digitrax controller .    I agree  - other locos I have fitted with stay alive only run for a matter of seconds when the power is killed.  This thing just keeps twitching away.  I wonder if the "twitching" is a symptom of some kind of shorting in the circuitry.  

 

4 hours ago, Chuffer Davies said:

Also:  I’ve just checked and it is possible to insert the PCB upside down.  The top is marked on the PCB so worth checking you’ve got it the correct way round. I would predict that inserting it upside down could be fairly catastrophic.

Frank

Yes checked this - definitely the right way up.   Decoder on top.  

 

17 hours ago, Neal Ball said:

Sounds like a faulty decoder. I’ve had it before with a cheap decoder, threw it away and the loco was fine. (Quite a few years ago, not this Mogul)

Quite possibly.     

 

4 hours ago, Chuffer Davies said:

Just to be clear; with DCC there is a constant voltage to the track.  When your Digitrax controller says the loco’s speed is zero this is purely a code passing between the command station and the chip in the loco.  If the loco does not behave as expected this is a fault in the loco’s circuitry or chip.  I am starting to wonder if there is a problem in the alignment of the PCB in the socket in the loco that is causing leakage between the track feed and the motor feed? This would put the chip at significant risk of damage.  Have you tried reseating the PCB?  
Frank

Yes I understand, and I kill the power to the track by using the track power on/off button on the Digitrax controller.  I have removed the PCB - cleaned the contacts, reinserted it, with no improvement.

 

I think you may be correct about the loco circuitry or the alignment/ connection of the PCB within the loco.   I wonder if there is a batch of dodgy PCBs and I have been unlucky in finding two of them.  

 

Thanks again to all for comments and advice, it is much appreciated.  I've spoken to my model shop so will take the loco back tomorrow.  I'll suggest they try a different chip to rule that in or out.  Then maybe third time lucky if they are happy to replace the loco.  Other option is to obtain a new PCB or send the loco to DCC Supplies for investigation.   One thing is certain I am not risking another sound chip until I have a loco that runs perfectly under DCC .

 

One bit of positive news - the firebox LED works (very dimly).  I double checked following Harlequin's post above. Looks like  F0 and F1 need to be turned not just F1.

 

Despite all this - I really like this loco. Runs like a dream (when it runs properly).  The compensated centre driving wheels and sprung bogie really help.  I think it looks good as well.        

[Gopher]

The next exciting instalment on my faulty Mogul

 

After more comprehensive testing otherwise known as frigging about I have made a discovery.

 

The instructions state that function F1 operates the firebox flicker.  As mentioned by Harlequin and Neal - Function F0 needs to be operated.  I have discovered that when I turn on Function F0 as well as getting a periodic dim firebox glow, the loco also starts the celebrated twitching, even when the throttle is returned to zero.  If I turn off Function F0 the Loco behaves itself.  So it looks as if there is some kind of circuitry/decoder fault.  The Zimo sound decoder I hope to install operates the firebox flicker off a different function to coincide with coal shovelling sounds.  I am still reluctant to install a sound decoder, when clearly there is some kind of fault.

 

I am not sure whether the F0 conundrum accounts for the other behavioural problems the loco has i.e. when put in reverse carrying on running even when throttle is returned to zero.   The only way to stop the loco being to cut power to the track.  This was happening every time I ran the loco this morning (and before I discovered the power of Function 0).  I have not been able to replicate this in my running session this afternoon (although I did remove the PCB and chip to examine them under a magnifier - possibly re-inserting both cured this problem).  Also in my session this afternoon cutting power to the track stopped the loco from twitching (unlike yesterday when it seemed to have a life of its own).

 

I guess the bottom line is whilst I can live without a firebox flicker, I do not fully trust the loco not to possibly screw up another more expensive decoder.  Also having paid good dosh the thing should run to spec, and I should not have to compromise.