DCC capacitor question

I've had trouble with DCC locos stopping and taking a while to get
restarted form time to time, usually over points and the like. Note
that there are no capacitors across the motors here, which I know
cause trouble for DCC.
From reading around it seems likely that the root cause is the line
voltage to the chip dropping momentarily, and I have seen some
comments to the effect that this can be fixed by the addition of an
appropriate capacitor (presumably with a resistor) to keep the chip
powered during very short transient power loss, from dirty track,
points and the like.
Has anyone done this? What values are appropriate and on which
lines would one apply the fix? Presumably the red/black. Also,
what type of capacitor should one use?
Thanks,
Guy
Reply to
Just zis Guy, you know?
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Dirty track, wheels or pickups. Or insufficient pickups on loco.
There are DCC chips (eg. Lenz Gold and others) which can use an onboard store to hold electricity to keep power over a dead spot. Lenz call theirs USP.
This article might give you some DIY clues. I've not tried it:
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- Nigel
Reply to
Nigel Cliffe
On Thu, 9 Aug 2007 18:41:24 +0100, "Nigel Cliffe" said in :
So you'd think, but after finding the same problem with the almost-new 8F on a piece of track that was recently cleaned and rail-zipped, I'm not so sure.
Didn't know what the difference was between the Gold and lesser models, you learn something every day :-)
Thanks.
Guy
Reply to
Just zis Guy, you know?
todays daft suggestion - how about a short. Could it be your getting a short, power is cut off, loco runs fraction past short point from momentum, controller resets after time, power restored.
Does your controller indicate if got a short ?
Cheers, Simon
Reply to
simon
On Thu, 9 Aug 2007 22:05:38 +0100, "simon" said in :
Not half it does! It goes "Bzzzt" and the red light flashes, and the controllers all say "OFF"
Guy
Reply to
Just zis Guy, you know?
Just zis Guy, you know? said the following on 09/08/2007 23:13:
There might just be a subtle clue there :-)
Reply to
Paul Boyd
Are you sure it's not momentary shorts due to a mismatch between wheels and pointwork. Are your points wired to be "DCC friendly"? It might not be the loco that stops that is causing the problem, just that it's more sensitive. Are some decoders more of a problem than others?
Taking a while to restart again is usually due to the setting of the acceleration CV.
You can buy a kit of parts to fit to Zimo decoders or make your own:
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The principles are the same for any decoder and it's good info if you know how to identify the components and the connections (or know someone who does)
MBQ
Reply to
manatbandq
I reckon it's probably due to the points not being DCC friendly. I always change the connections on Peco and the like so that I wire up the blades to the stock rail they relate to. Helps solve the problem I find.
Ian J.
Reply to
Ian J.
On Fri, 10 Aug 2007 11:17:12 +0100, "Ian J." said in :
Could be. There is a website for that, isn't there? I am using a mix of electrofrog and insulfrog points, I certainly find that the levels over the points are critical (that took a while to work out, as well!).
OK, I'm off on me holibobs now so will get back to this in a while. Thanks, chaps.
Guy
Reply to
Just zis Guy, you know?

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