Unable to adjust start up speed on new hard wired Dcc loco

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Neilm
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Unable to adjust start up speed on new hard wired Dcc loco

Postby Neilm » Thu Nov 10, 2016 7:06 pm

I' m new to this hobby so forgive me if my terminology isn't correct:
I've just hard wired my first loco with a Bachman Dcc 8 pin decoder (in a hornby 4mt - not dcc ready) and the engine runs up and down in the correct direction, but I can't get the loco to pull away slowly, it's as if I'm using a dc controller. The controller is a dynamis ez command and I've played with the speed steps but there is no difference. With other loco's I've put decoders in you can pull away from a crawl, (although they were both dcc ready), but not with the hard wired loco. Should I have to use a Hornby decoder, I've used the same Bachman decoders in non Bachman loco - one Vitrains class 37 and a Heljan Bayer Garrett. Any ideas please.

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Flashbang
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Re: Unable to adjust start up speed on new hard wired Dcc lo

Postby Flashbang » Thu Nov 10, 2016 8:32 pm

Hi
Try setting CV2 (start voltage) to a low value. Say 1 or 2 and then see what it pulls away like using 128 speed steps.
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Neilm
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Re: Unable to adjust start up speed on new hard wired Dcc lo

Postby Neilm » Thu Nov 10, 2016 8:48 pm

Thanks fir your reply flashbang. Tried it but still the same, doesn't seem to be any difference.

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Flashbang
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Re: Unable to adjust start up speed on new hard wired Dcc lo

Postby Flashbang » Thu Nov 10, 2016 8:57 pm

Ok
I would now try turning off DC operation via CV29 setting it to a value of 2 or 34 if long address is used.
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Bigmet
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Re: Unable to adjust start up speed on new hard wired Dcc lo

Postby Bigmet » Fri Nov 11, 2016 10:39 am

Sometimes it has to be faced that a decoder has too much output even when CV2 is set at minimum value, to suit a particular motor which is a just that bit more efficient than the general run and starts on a breath of current. Try every adjustment the decoder offers, but if that doesn't sort it, an alternative decoder may have to be the solution.

I'd suggest a Lenz Standard (good for practically all current OO RTR, it's the one I regularly use and expect the smoothest 'creep' in and out of motion) or if that fails to obtain a smooth start and stop, then a Zimo (the fairly new MX600 offers a lot for the low price).

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Re: Unable to adjust start up speed on new hard wired Dcc lo

Postby BromsMods » Fri Nov 11, 2016 12:03 pm

The problem you have might relate to the version of Bachmann decoder. See the link from https://clarahost.clara.net/www.bromsgr ... ion4mm.htm for 36-553 and 36-554 decoders.

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Re: Unable to adjust start up speed on new hard wired Dcc lo

Postby mahoganydog » Fri Nov 11, 2016 4:58 pm

Hi Neilm,

Does it start suddenly when you get some way up the controller dial? I remember from when I worked in a model shop that sometimes the suppression capacitors had to be removed from the motor on older models to get them to start at low speed.

Just a thought.

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RAF96
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Re: Unable to adjust start up speed on new hard wired Dcc lo

Postby RAF96 » Sat Nov 12, 2016 8:46 am

I was going to suggest bemf but I see that is covered in Bromsmods linked out document above.

Note also that due to compatability problems some command stations do not support DC running - loco-0. LH100 and also EZ dynamis from memory.
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Neilm
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Re: Unable to adjust start up speed on new hard wired Dcc lo

Postby Neilm » Sun Nov 13, 2016 4:47 pm

Thanks for all your advice, but still had no joy, took it out and hard wired it into a ringfield motor driven Britannia class loco which works perfect. Next project is to chip an old 3 pole motor driven engine, is it possible, watch this space for queries please.


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