Accessory points decoder problem

[veejay]

Hi Everyone,

 

Another newbie i'm afraid!

 

I've been looking online for a solution to this but so far no luck.

 

I have a Hornby 00 mixed freight set up which is going along fine. I've now bought R8247 points decoder with surface point

 

motors. On programming the select controller the point motor works fine up until when I place a loco on the track, at which point either the loco or the point motor do not function. Am I right in thinking that this is a power problem, or lack of?

[Fishmanoz]

Hi veejay, welcome and it sure sounds like it. Will it work while both locos are stationary, or only when they are running? If it doesn't work with the locos stationary, then check that you have good connections from Select to the track and from the 8247

 

to the track. The locos draw very little power when not running so shouldn't affect point operation. You are not using an analogue power clip or power track anywhere are you, they degrade the DCC signal as they have a capacitor in them? If so, it's easy to

 

get it out by flipping open the cover and clipping it off.

 

Irrespective, if you plan to expand your number of locos and have more points, I would suggest buying the optional 4Amp supply, which will almost certainly solve your problem. However, if you

 

are thinking to upgrade to an Elite, it comes with the 4Amp, so consider buying it now so you don't end up with 2 supplies. If you are thinking of going eLink with Railmaster at some point, you still need to get the 4Amp as that comes only with the 1.

[veejay]

Hi Fishmanoz,

 

Many thanks for your info! As it happens when I bought the decoder it has come with a power clip which has a black sticker with DCC on it underneath? With this attached, and decoder wired to that I get no running locos at all.

[Fishmanoz]

That's weird veejay. You really need to do some testing to sort this out and a multimeter would be handy if you have one. However, lets try to check it out one step at a time. So no decoder or power clip and both locos run fine? Try connecting the decoder

 

power clip without the decoder attached. Does it still work ok? If not, the power clip may still be not making good connection, or may have some sort of almost short. Also try removing the power track from your layout and connect using the power clip. Do the

 

trains run ok or are they slow or not working at all.

 

If you have a multimeter, try this: on AC range, disconnect the Select and measure the volts at its output terminals. Remember the result. Now connect the wire that goes to the power track and measure

 

the volts at the track end. Still the same? If so, now connect the power track only, not the whole layout. Measure across the tracks. Still the same? Now put into the whole layout and measure across the tracks. Still the same? Now disconnect the wire from

 

the power track and connect to the power clip and measure across its outputs to the track? Still the same? Now connect the clip to a single piece of track and measure across the track. Still the same?

 

If the voltage dropped significantly on connection

 

of anything, then the thing you connected has a fault somewhere. If all is OK to this point then, with the full layout connected, try adding each loco and the decoder to the track individually. Any of them make the voltage drop significantly and more then

 

the others? If so, then that particular item is the problem.

 

My point is there must be a short or near short somewhere in your system, or maybe a poor connection. The thing is to add items one by one until you find the one causing the problem, then

 

check what is wrong with it. You need a multimeter to do this properly though.

[Gregd99]

I don't have an 8247 and only have access to the online documentation.

 

It sounds as though you are short circuiting or perhaps connecting a lowish impedance across the tracks when you connect your decoder.

 

dcc should be polarity independent

 

and so there is no need to worry about connecting + to + and - to -.

 

it sounds basic but are you sure that you are connecting the power clip to the dcc port on the 8247 and not one of the output ports?

[veejay]

Hi Fishmanoz, Gregd99,

 

Apologies for taking so long to reply, unfortunately work got in the way of things!

 

I've tried the suggestions you have given regarding using a multimeter and there's no loss of voltage in any of the scenarios. Both

 

locos run fine with the points motor connected, however the points motor now seems only to be working either in one direction or not at all. I'm still wondering if this is a lack of power issue and that a greater power supply would be required?

[Fishmanoz]

Veejay, this setup should, and I emphasise should, work. For a start, the decoder includes what is called a Capacitor Discharge Unit, CDU, so, in the first instance, the power to throw the point comes from within the decoder. After it has fired, then it

 

draws a low current to recharge. With the few things you have, the 1Amp supply should be adequate.

 

So a couple more questions. Will the decoder throw the point motor in each direction with no point attached to the motor (this eliminates the possibility

 

of poor mechanical alignment gumming things up)? Are you really sure you have the black wire going to the centre common connection on the decoder port? And finally, is it the same no matter which of the 4 ports is used?

 

If the first answer is no, and

 

the other 2 yes, I'm thinking faulty decoder. However, there is still a s,all chance the 4Amp supply might fix it, but I emphasise small chance. The fact you are getting full volts everywhere indicates to me this is not the problem.

[stevecamden]

If you have followed all the good advice re sticking the wires in the right outputs etc then I think I would consider resetting Select to factory settings and try that. I'd also probaly re-address on the programming track the decoder. I don't think with

 

the Select that you can reset the decoder to factory settings - I can't remember if the Select will let you do this! Sometimes these electronics throw strange wobblies ( technical term) that are inexplicable and you just have to unplug and reset everything!

[Fishmanoz]

It's a bit like The IT Crowd - turn it off and turn it on again, then ring me back if it still isn't working.

Steve, the Select will certainly not do a decoder reset, and it doesn't have a programming track output. You just have to make sure that the

 

thing you want to program is the only thing on the layout at the time - very annoying for those with Elite programming track experience.

[Amac]

Hi all.

I recieved a R8247 decoder for christmas, tried wiring up my point #s today and got nothing, I followed theinstructions, after I strained my eyes reading them and only pluged in a point motor to connection no. 1 for programming, I got nothing, no movement at all. I stripped it all out and ran my motors through a DC system and all motors worked. 

What did I do wrong?

[Fishmanoz]

Hi Amac, welcome to the forums.  I can see you know how to do a forum search too to dredge up this 3 year old thread.  I suggest it is always better to start your own.

 

Given you have only one decoder at present, there is no need for any programming just now.  It comes default with ports 1-4 set and can be left as is, unless of course you are using Select and so need to program it to something above 60 to get it into the Select address range for accessory decoders.

 

So tell us what controller you are using, what you have done on the programming track and exactly how you have wired it to the track and to your points (which wire to which connection on the port) and we can help further.