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Discussion Starter · #1 ·
I am using a Digitrax Super Empire Builder for DCC Control. I have noticed that on occasion when two or more locos are running that one local will suddenly stop without warning. When this happens the speed control on the DT400 throttle reads zero for the loco concerned. Once the throttle knob is turned the loco starts moving again. Sometimes the loco concerned after it starts moving again cannot be immediately controlled and several seconds will elapse before the throttle regains control.

Today my grandson was using a UT 4 to control a third loco, the loco that he was controlling kept stopping, two others controlled from the DT 400 were OK. Initially I thought that that he was stopping the loco then I realised the loco he was controlling was stopping because the speed had reset to zero, but this is not as apparent from the UT4 as it would be from the DT 400.

I thought that I might have a loco with a capacitor that I had missed and the Bachmann 108 DMU was my prime suspect. I then made the mistake of taking this apart and then spent about an hour trying to relocate a tiny little plastic lug in the flywheel.

I am 99.9% positive that capacitors have been removed from all my locos. Can anyone offer any explanation for this erratic behaviour which has now happened to at least 4 locos.
 

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QUOTE (Peter Armond @ 1 Sep 2008, 06:25) <{POST_SNAPBACK}>I am using a Digitrax Super Empire Builder for DCC Control. I have noticed that on occasion when two or more locos are running that one local will suddenly stop without warning. When this happens the speed control on the DT400 throttle reads zero for the loco concerned. Once the throttle knob is turned the loco starts moving again. Sometimes the loco concerned after it starts moving again cannot be immediately controlled and several seconds will elapse before the throttle regains control.

Today my grandson was using a UT 4 to control a third loco, the loco that he was controlling kept stopping, two others controlled from the DT 400 were OK. Initially I thought that that he was stopping the loco then I realised the loco he was controlling was stopping because the speed had reset to zero, but this is not as apparent from the UT4 as it would be from the DT 400.

I thought that I might have a loco with a capacitor that I had missed and the Bachmann 108 DMU was my prime suspect. I then made the mistake of taking this apart and then spent about an hour trying to relocate a tiny little plastic lug in the flywheel.

I am 99.9% positive that capacitors have been removed from all my locos. Can anyone offer any explanation for this erratic behaviour which has now happened to at least 4 locos.

*** This is not easy to troubleshoot. Additionally I don't spend a lot of time with D so am a bit rusty there....

a few thoughts....

***Do you use the track bus for operating or powering accessories? If so, disable the latest coule you added and see if the problem disappears. Its not unknown for an accessory product to add garbage to the bus with strange results.

***If you are using the track bus to power point motors stop doing it! This WILL very frequently cause all sorts of random and annoying issues. Use a separate power supply for all high current devices like point motors in particular.

***Over time digitrax systems can become clogged and erratic if either the loconet bus has low voltage or if unused loco's are not properly dropped or dispatched properly after use - its not common on "lone use" home layouts as a problem but clubs have to have a routine in place that insists on it and a routine for say monthly resetting the command station.

Low voltage on the loconet structure can trigger all sorts of wierd problems between controller and decoder, as the digitrax waveform is already a wee bit less than ideal, being decidedly sloped at the start of every wave....

Check all the cables between command station and any loconet panels, and measure the voltage at the most distant UTP (layout panel) while the system is actively running trains. If its lower than 12v then add small regulated DC power pack (plug pack type is enough) with 12DC output to one of the UTPs.

Digitrax UTPs have a socket to allow a power supply to ge added to a UTP to boost command signal strength.

***Try resetting the DB150 and purging the system of all loco numbers

*** Try telling it to never send an aotumated stop or purge command: It could also be that the DB150 is for some reason simply dropping the loco -digtrax an be set up to auto stop or drop a loco that hasn't received a new command for a certain time aand this may have inadvertently been triggered. Set the DB150 option switch 15 to open and the option switch 14 to closed. This should stop all automated purging.

No promises, but the above might help....

Richard
 

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Discussion Starter · #3 ·
Richard,

Many thanks for your response.

I can eliminate the first two as I do not have anything connected to the track bus other than track, points are operated independently analogue off a separate transformer. The same also applies to the turntable.
QUOTE (Richard Johnson @ 1 Sep 2008, 06:21) <{POST_SNAPBACK}>***
Check all the cables between command station and any loconet panels, and measure the voltage at the most distant UTP (layout panel) while the system is actively running trains. If its lower than 12v then add small regulated DC power pack (plug pack type is enough) with 12DC output to one of the UTPs.

Digitrax UTPs have a socket to allow a power supply to ge added to a UTP to boost command signal strength.

This may well be the problem; I will check this and your other suggestions later this week and revert in need.

Thanks again.

Peter
 

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Hi Peter Richard Willcox here,

try this,
plug in your DT400 directly into the DCS100 command station. Ref page 94 of the DCS100 manual DCS100 option switch setup. Set Ops 5 to closed, then ops 39 to closed, then return your DCS100 to the run state.
This in effect clears the stacks in your command station. Just read the relevant section as detailed and give it a try it normally works for the odd funny thing that you can't work out.
regards
Rich
 

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Discussion Starter · #5 ·
QUOTE (Makemineadouble @ 2 Sep 2008, 01:11) <{POST_SNAPBACK}>Hi Peter Richard Willcox here,

try this,
plug in your DT400 directly into the DCS100 command station. Ref page 94 of the DCS100 manual DCS100 option switch setup. Set Ops 5 to closed, then ops 39 to closed, then return your DCS100 to the run state.
This in effect clears the stacks in your command station. Just read the relevant section as detailed and give it a try it normally works for the odd funny thing that you can't work out.
regards
Rich

Hi Richard thanks, I wil give it a try later.

Regards

peter
 

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QUOTE (Makemineadouble @ 2 Sep 2008, 07:11) <{POST_SNAPBACK}>Hi Peter Richard Willcox here,

try this,
plug in your DT400 directly into the DCS100 command station. Ref page 94 of the DCS100 manual DCS100 option switch setup. Set Ops 5 to closed, then ops 39 to closed, then return your DCS100 to the run state.
This in effect clears the stacks in your command station. Just read the relevant section as detailed and give it a try it normally works for the odd funny thing that you can't work out.
regards
Rich


***Ummmm Richard... The Empire builder has the DB150, not the DCS100 as its base station. Its an older command station type and the settings are different aren't they?

I was interested in your response re resetting the DCS1oo though - thanks

Richard Johnson
 

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Aggggg...... yes your right, if it's a DB150 I'll have to look it up.........my manuals are all packed away ready for a move.

Peter just check what the DB150 manual says the principle will be the same the DB150 has much smaller stacks (20) I
think, you'll have to train your grandson to purge a loco number or address when changing control Ditto for yourself !

should have bought the DCS100 !
regards
 

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Discussion Starter · #8 ·
QUOTE (Makemineadouble @ 2 Sep 2008, 16:51) <{POST_SNAPBACK}>Aggggg...... yes your right, if it's a DB150 I'll have to look it up.........my manuals are all packed away ready for a move.

Peter just check what the DB150 manual says the principle will be the same the DB150 has much smaller stacks (20) I
think, you'll have to train your grandson to purge a loco number or address when changing control Ditto for yourself !

should have bought the DCS100 !
regards
Rich,

Richard J is correct the DB150 is the base station not the DCS 100. However there is a similar procedure for the DB150 described in the manual.
We have a public holiday here tomorrow so I will experiment!
 

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Discussion Starter · #9 ·
I "purged" the system as suggested by Richard J, at least I think that's what I did!!, and it seems to have worked. I had 4 locos running this morning over the course of a couple of hours and there was no repetition of the problem. Many thanks to both Richards.

On a separate issue I was thinking this afternoon how good DCC is when it comes to fine control for children. My eldest grandson (Age 7) now knows how to call up a loco on the throttle. Today he successfully slowly negotiated the loco from the loco shed on to the turntable and sent it on the correct exit track to pick up some coaches and run on the rest of the layout. With my help as signalman he successfully ran round the train at the through station and returned to the terminus.
 

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***Thats good news - well done and thanks for letting us know, its always a high point of my day when advice helps another modeller! I'm sure RW thinks the same way.

Re the young one, thats great to hear - They really can be excellent operators if taught well - and he obviously has a good teacher! As you've noted, they always seem to be really quick to pick up on DCC control too.

It sounds like you have the nucleus of a good operating team, a good layout partner and a future railway modeller alongside you!

Kind regards

Richard
 
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