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hornby loco decoder

2611 Views 15 Replies 7 Participants Last post by  Brian Considine
i have just opened the packet for the hornby decoder and the pale purble lead is not connected to the plug. is this normal/needed and can i repair it? thanks andy
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This is normal. It isn't supposed to be connected.
do i insulate the end then? thanks for help
Yes, unless it's needed for a function on your loco. What loco are you converting?
its a hornby q1 class. not running any lights or other functions at moment so i dont need it i think
what is the purple lead for, as I have wondered it my self and just took it off.
Many thanks
The purple wire is Function output D (normally controlled by f2) for extra lights etc. Here's a link to fitting a Q1 with a decoder. http://www.bromsgrovemodels.co.uk/hornbyq1dccinstr.htm
the guide mentions removing the capacitor is this the recommended way as the insrtructions dont mention it
Try it with the capacitor left in place first. Only if there are problems running should it be removed.
QUOTE (poliss @ 16 May 2008, 03:09) <{POST_SNAPBACK}>Try it with the capacitor left in place first. Only if there are problems running should it be removed.

***I disagree.

* It is a component needed for suppression under DC running only

* Once a decoder is added it serves absolutely no valid purpose.

* No loco will ever run better with it in place and most will clearly work better with it gone.

* In particular it interferes slightly with the motor to decoder relationship and it will always prevent back EMF working at its best. It should be removed 100% of the time.

Think about it logically - if you leave it in the loco may run OK to you but how will you ever know if really its as good as it can be running wise?

Richard
DCCconcepts
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Engine Shed producers of the Progidy system advise the removal all suppressors when fitting a chip.
Removal/leaving capacitors (& the "spin offs" such as CE issues) is yet another subject done to the death on MRF & other forums.

AFAIK no manufacture or distributor of decoders (except maybe one - & I cannot remember which one) recommend leaving capacitors in place.

Richard sums up the whole issue very neatly.
QUOTE (Brian Considine @ 16 May 2008, 10:44) <{POST_SNAPBACK}>AFAIK no manufacture or distributor of decoders (except maybe one - & I cannot remember which one) recommend leaving capacitors in place.

Richard sums up the whole issue very neatly.
ZTC "Any manufacturers' motor suppression components connected across the motor terminals
must not be removed. These will not affect digital control operation. These components
help reduce radio frequency interference from the motor, and are a legal requirement in
most countries and jurisdictions. Also, removing them can have a detrimental affect on the
operational performance of a DCC decoder" from their installation instructions. Yeah, right.

There are plenty who will not tell you to take supression components out because of a misguided, IMHO, interpretation of the EMC regulations. What you do to your own locos (i.e. removing supression components) is your own business and is not a legal issue unless you do it and resell the loco in the course of a business. Even then, it's not an issue if the loco and decoder meet the regs, it's just harder to prove.

I almost always remove suppression components, especially as they can take up valuable space in N.

Andrew Crosland
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