Loco with a mind of its own - Short Circuit?

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8vchris
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Loco with a mind of its own - Short Circuit?

Postby 8vchris » Thu Dec 07, 2017 1:14 pm

Ok, so my Lima class 87 that I converted to run on DCC has been causing some issues.

The background - Post conversion it runs great on DC, happily trundles round with full control. On DCC however it won't, as soon as its on the rails it shoots off with no regard to the speed dial, current channel the Hornby Select is on or anything else. Only two things will show any sign of doing as their told; 1 - the directional controls 2 - the emergency stop. All else is uncontrollable. The tracks themselves are immaculate, theyre polished to within an inch of their lives, as are the wheels on the loco, theyre also like new. The track has been swapped out for newer to rule it out and the behaviour is the same so this makes me believe its either the controller or the loco, with the latter the likely culprit. Having read loads online, here and elsewhere, about runaway trains im beginning to think the issue may potentially lie with a short circuit. Queue my diagram;

Image

This is the current bogie. It has pick ups on all four wheels. Am i right in saying that having pickups on all four wheels and leading to one single spindle that runs to the black wire would cause a short? Surely, the pickups would be better sited on the opposite to the motor pickup? Will insulating two of the pickups on one side, one per axle, then remove the short forcing all power to the black wire, chip and then the motor due to a cleaner, tidier DCC waveform?

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RAFHAAA96
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Re: Loco with a mind of its own - Short Circuit?

Postby RAFHAAA96 » Thu Dec 07, 2017 1:56 pm

The basic wiring for DCC is this (usually installed by way of a socket but can be wired direct from the decoder to the loco)

Red wire to right side rail wheels pickups
Black wire to left side rail wheels pickups

There must be no connection between the left and right sides so your diagram shows you have a direct short if they all collect to a black wire as you say they do.

You can have as many pickups as you like, in fact the more the better but they must be separated side to side.

Orange wire goes to one motor brush
Grey wire goes to the other motor brush

There MUST NOT be any connection between the motor and the rails other than by way of the decoder.

If you want lights then come back after you have sorted the motor part of the wiring out.
Rob
RAF Halton Brat - 96th Entry
http://www.halton96th.co.uk

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8vchris
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Re: Loco with a mind of its own - Short Circuit?

Postby 8vchris » Thu Dec 07, 2017 4:03 pm

RAFHAAA96 wrote:The basic wiring for DCC is this (usually installed by way of a socket but can be wired direct from the decoder to the loco)

Red wire to right side rail wheels pickups
Black wire to left side rail wheels pickups

There must be no connection between the left and right sides so your diagram shows you have a direct short if they all collect to a black wire as you say they do.

You can have as many pickups as you like, in fact the more the better but they must be separated side to side.

Orange wire goes to one motor brush
Grey wire goes to the other motor brush

There MUST NOT be any connection between the motor and the rails other than by way of the decoder.

If you want lights then come back after you have sorted the motor part of the wiring out.
Rob


thanks very much for such a fast response, why is it that it runs quite happily on DC or is it simply far more forgiving?

Dad-1
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Re: Loco with a mind of its own - Short Circuit?

Postby Dad-1 » Thu Dec 07, 2017 4:06 pm

If you had a short circuit you would either burn out the decoder, or have the control system shut down.
You wouldn't have any running !
I think this may be that you need considerable adjustment to the back EMF settings. Here you have a
major problem in as much as the Select can't adjust these. Also if you're using the Hornby R8294 std
decoder you can't change the required CV's anyway.

The answer once happy with connecting up the correct leads would be to get either a Lenz or Zimo decoder
where there are vast adjustments available BUT you can't alter the required CV's with a Select.

Geoff T.
Remember ... I know nothing about railways.
viewtopic.php?f=22&t=32187 and Another on viewtopic.php?f=22&t=28436&start=60&st=0&sk=t&sd=a

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Flashbang
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Re: Loco with a mind of its own - Short Circuit?

Postby Flashbang » Thu Dec 07, 2017 4:07 pm

Hi
The pick ups cant be quite as you have shown them. Whether on DC or DCC as shown it would place a full short circuit across the rails and control system! There must be a insulated break / gap between the left and right hand sides wheel wipers.

Runaways on DCC are often caused by the decoder not understanding the DCC signals. The decoder 'sees' the full rail volts and thinks its on DC and at full power and so takes off like a scolded cat! These decoders need to have their DC operation via CV29 disabled. You cannot do this with a Select. So you would have to find someone who can do it for you - Friend with a better DCC system, local model shop or even a model railway club.

What firmware version is the Select at? The start up display shows this. Version is 15 or 1.5 is the very latest firmware for the Select. So if your display shows 11, 12 or 13 as the first set of digits you may like to consider sending back to Hornby for a firmware update. Cost I understand is around £15.00 but you have to contact Hornby first to obtain a returns number before sending it back. Version 1.5 is apparently a vast improvement in the DCC output wave form from the Select. |Details are here... https://www.hornby.com/uk-en/returns
Broken? It was working correctly when I left it.

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8vchris
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Re: Loco with a mind of its own - Short Circuit?

Postby 8vchris » Thu Dec 07, 2017 4:36 pm

Now having said that i must have been confusing it for another loco as it picks up from the axle but two of the wheels are insulated down one side so that blows that idea out of the water. After taking the loco apart again and checking the wiring and joins etc

As you say, perhaps finding someone to cancel the DC capability might be the best move from here. The select I'm using is on firmware v12 so an update may the best way forward. If using the Hornby decoder, am i going to have this issue again any time i use them, surely this can't be a common issue? I'm loathe to spend more on different ones as the moment as I have another 3 new Hornby decoders sitting in their packets still.

Dad-1
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Re: Loco with a mind of its own - Short Circuit?

Postby Dad-1 » Thu Dec 07, 2017 4:55 pm

I primarily use Selects, have 5 of them, I know and understand their limitations.
Hornby's own decoder works fine in NEARLY all my locomotives and I have in excess
of 80. SOME locomotives have problems and that's directly linked to the capabilities
of the drive motors fitted in the locomotives.
I wonder if that's where your problem lies, on a couple of locomotives where I expected
some troubles I fitted Zimo decoders at 2.1/2 times the price of the Hornby and every one
has tamed the loco without even having to spend time with a colleague who would have
messed about for me had it been required. He has a radio controlled Digitrax system.

Some locomotives with Bachmann 21 pin decoders needed taming by adjusting the back EMF
settings to get them running in a usable fashion on a Select. Everything I have is tuned to
work with my Selects that I much prefer using rather than the IR wireless links on the Bachmann
Dynamis.

Geoff T.
Remember ... I know nothing about railways.
viewtopic.php?f=22&t=32187 and Another on viewtopic.php?f=22&t=28436&start=60&st=0&sk=t&sd=a

GWR_fan
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Re: Loco with a mind of its own - Short Circuit?

Postby GWR_fan » Thu Dec 07, 2017 7:19 pm

8vchris wrote:................. If using the Hornby decoder, am i going to have this issue again any time i use them, surely this can't be a common issue? I'm loathe to spend more on different ones as the moment as I have another 3 new Hornby decoders sitting in their packets still.


I have found that the R8249 does not behave nicely on DC power. For me the basic R8249 is fine but you need to deactivate analogue running as stated or you will experience erratic analogue running and as you have seen the loco running off at full power or worse still randomly selecting reverse direction while going the opposite direction.

Hornby decoders (other than the Sapphire) are basic as is the Select controller. If you wish to expand your digital interest then to avoid further running issues, forget that Hornby make digital systems and look to a non-model railway manufacturer and go with a specialised digital manufacturer. Not what you want to hear but unfortunately what you have is too restrictive and will most likely persuade you to lose interest in DCC.

Bigmet
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Re: Loco with a mind of its own - Short Circuit?

Postby Bigmet » Fri Dec 08, 2017 10:10 am

8vchris wrote:...If using the Hornby decoder, am i going to have this issue again any time i use them, surely this can't be a common issue? I'm loathe to spend more on different ones as the moment as I have another 3 new Hornby decoders sitting in their packets still.

The approach I use might help. What I do with decoders is try the cheaper and simpler (Lenz Standard) first. If that's OK, then we are done, and that covers pracitcally everything. But if it cannot handle a mechanism, then I try a Zimo at slightly more money - if buying now that would be an MX600 type - and so far everything has responded to the Zimo treatment.

So you just try the Hornby decoders, but buy yourself a Lenz standard as a standby as a first step...

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8vchris
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Re: Loco with a mind of its own - Short Circuit?

Postby 8vchris » Sat Dec 09, 2017 5:47 pm

Thank you for all of your help, I've bought a Bachmann decoder from a local shop and tried that but it unfortunately didn't make a difference to the running of the loco. I swapped it and one of the other Hornby decoders into a class 108 dcc ready two car dmu and its the same result there, the only good point is that the cab and directional lights all work. I'm considering that the issue lies with the select controller and with the inability to edit the cv values, I'm thinking it might be better upgrading to a better control system to let me disable the DC option. That said, the booklet that came along with the Bachmann decoder said that the dc option was disabled unless intentionally activated so I have no idea why its behaving as it is. I can see why some advice i was given (from the local model shop) was stay away from dcc but I'm determined to stick with it as the end result should be worth it. With that in mind, and I know it was commented on to forget Hornby digital systems, but is the eLink/RailMaster system worth looking at?

mjb1961
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Re: Loco with a mind of its own - Short Circuit?

Postby mjb1961 » Sat Dec 09, 2017 7:35 pm

NCE POWERCAB is what I would reccomomend,,,good value for money,reliable and does about everything you require,,,,look them up ,,

Bigmet
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Re: Loco with a mind of its own - Short Circuit?

Postby Bigmet » Sat Dec 09, 2017 7:51 pm

8vchris wrote:... I can see why some advice i was given (from the local model shop) was stay away from dcc...

Model shop with a death wish?

DCC is a very good control system, but the implementation in starter equipment like the Select is weak; you get none of the main benefits beyond independent control of locos. Go to a show with DCC specialist retailers present or directly to a DCC specialist retailer to get an idea of what it can really do for you. There's a half dozen good brands well represented in the UK, and all have something of their own to offer. You can have a console that looks like it belongs on Starshit Enteritis, handheld controls big enough to need two hands, little handsets, wireless handsets, thought control - oh no, not that - but control via apps on smart phoney tabletty things that you might already own...

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Peterm
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Re: Loco with a mind of its own - Short Circuit?

Postby Peterm » Sat Dec 09, 2017 10:56 pm

Rather than stay away from DCC, I'd stay away from that particular model shop. Whereabouts are you. Digitrains in Lincoln would help, DCC Supplies, Holt Heath, Worcestershire, South West Digital, etc. If none of these are close, let us know what county you live in and someone can point you in the right direction.
Pete.

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Re: Loco with a mind of its own - Short Circuit?

Postby GWR_fan » Sun Dec 10, 2017 2:36 am

8vchris wrote:...............and I know it was commented on to forget Hornby digital systems, but is the eLink/RailMaster system worth looking at?


I suggest that you look both online and You-Tube videos before commiting yourself to e-link. Many have success and many do not. I feel that like the Select the e-Link is a very basic programme. I use both NCE and Roco. Earlier this year I disposed of twelve digital Hornby trainsets with the e-Link controller. I was tempted to keep two for myself but after research online decided to stay away from potential trouble. I suggest sticking with a reliable standalone DCC system like say the Lenz and you will be set for life. You may pay a little more but in the long term you will be better off. Do not be swayed by cheap systems just because they are inexpensive.

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8vchris
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Re: Loco with a mind of its own - Short Circuit?

Postby 8vchris » Sun Dec 10, 2017 11:24 am

I'm in Northern Ireland so my options, from what i can see, are rather limited. Having been given plenty of advice here and based on someone else on another forum having the same issue I think the play will be send the Select back to Hornby to have its firmware updated to the latest version (mine is v1.2, latest seems to be v1.5). If it works then it will be £15 well spent and will do for the meantime, if not then it can be sold with the latest firmware. Failing that fix, I'll invest in another non-Hornby system. I still think its mad that a Hornby controller won't control Hornby locomotives, latest firmware or not, that must be a serious oversight on the part of Hornby! If this is the experiences newcomers have with the out of the box train sets it's no wonder Hornby are struggling.


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