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Short circuit


russ p
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Have you used any copper clad strips at baseboard ends?

I've had occasions where the gap looked good, but there was a minute whisker of copper that was virtually invisible.

 

Cheers,

Mick

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Have you fully isolated the two halves ,fishplates etc., not just dividing the bus?

How have you connected the droppers to the bus, is there plenty of physical separation between the two bus wires?

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I've actually cut cables and removed track to separate the layout

I've connected the droppers to the speaker cable by separating the wires and connecting the droppers with scotch locks

This is connected to the flat twin and earth bus with terminal blocks

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Hello. You said you were using speaker cables as droppers. If these are are the ones that are a pair of same coloured wires with one having a tracer stripe, then it is quite easy just to cross one set over, even if you think you have checked them previously (you can sort of develop a blind spot, and keep missing the fault, well I can anyway). How easy is it to disconnect all droppers from the bus bar and connect back one at a time, checking for a short after each one? 

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I still have an on-going problem with a point motor.

I've checked, double checked, re-checked and it still doesn't want to work.

Me thinks it might be the motor itself - but a pain to replace as it's in the tightest spot ever.  Might be easier just ti take it out all together :/

Edited by Sir TophamHatt
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Hello. You said you were using speaker cables as droppers. If these are are the ones that are a pair of same coloured wires with one having a tracer stripe, then it is quite easy just to cross one set over, even if you think you have checked them previously (you can sort of develop a blind spot, and keep missing the fault, well I can anyway). How easy is it to disconnect all droppers from the bus bar and connect back one at a time, checking for a short after each one?

 

The speaker cable is red and black.

Its not that easy to disconnect droppers as theybare scotch locked onto the speaker cables

I've tried disconnecting these from the bus but to no avail.

Point motors will probably be another cause of my forthcoming mental breakdown!

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The speaker cable is red and black.

Its not that easy to disconnect droppers as theybare scotch locked onto the speaker cables

I've tried disconnecting these from the bus but to no avail.

Point motors will probably be another cause of my forthcoming mental breakdown!

 

 

If you unclip the scotch lock you can get a flat head screwdriver under the blade, at the same time squeeze the scotch lock case closed with pliers, the blade should now pop out the top of the scotch lock case where you can get the pliers onto it and pull it out and free the wires.

The scotch lock can be reused but it need to be placed to the left or right of where it was originally placed.

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I can't offer any better advice than that which as already been given, basically divide the offending track into smaller sections which can be tested individually until the fault is located.

When you do find the fault please let us know as I don't know about other people but it's niggling me.

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I certainly will everyone has been a great help.

Hopefully I'll be in the railway room tomorrow night.

Would be nice to find it as my track diagram panels will be ready on Friday so after wiring the other part of the layout I'd like to install the point motors and wire them up

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If I read your description correctly you have various lengths of speaker cables running from the bus to groups of droppers. Can you disconnect speaker cables from the bus one at a time to try and find which set is causing the problem. Or is the whole of this section fed from one set of speaker cables from the bus?

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Can I suggest making yourself a simple lamp tester ? A bulb and holder two crocodile clips,wire and a battery (I actually adapted an old bycicle lamp) Disconnect any power to the track and clip your lamp tester to the track with the crocodile clips. If it lights up you have a short. Now you can do as suggested, Isolate a section of track then clip on your lamp tester and if it lights up start disconnecting wires till it goes out (you may have more than one fault in a section so keep going till the light goes out) once the light goes out find out what was wrong with the last wire you disconnected, sort it and carry on 're connecting wires till you get a light again, rince and repeat

 

You may then find a common cause of the fault, pointing you where to look for more

 

old school I know but it saves you connecting and disconnecting power supplies and constantly trying to make contact with multimeter probes to find your fault. It also comes in handy as you add in more sections of track wiring, lighting up straight away if you cross a wire, rather than you trying to find multiple faults later on

 

Hope this helps

 

Cheers

 

Matt

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If I read your description correctly you have various lengths of speaker cables running from the bus to groups of droppers. Can you disconnect speaker cables from the bus one at a time to try and find which set is causing the problem. Or is the whole of this section fed from one set of speaker cables from the bus?

I can disconnect but there are others further down the bus

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I can disconnect but there are others further down the bus

But if it is one particular section or dropper that is causing the short, the short will disappear when you disconnect from the bus then you can concentrate on that speaker lead, droppers and area of track work.

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But if it is one particular section or dropper that is causing the short, the short will disappear when you disconnect from the bus then you can concentrate on that speaker lead, droppers and area of track work.

 

Only if you have all the sections isolated from each other. If you are simply using a bus and droppers to get over any bad rail joints and haven't built in isolation then removing one dropper will not show where the issue is (or isn't) 

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Only if you have all the sections isolated from each other. If you are simply using a bus and droppers to get over any bad rail joints and haven't built in isolation then removing one dropper will not show where the issue is (or isn't)

That struck me after I replied. Well, it was late. 

Edited by BoD
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Sorted! I removed the bus and traced it to a short radius Y point......

Bloody electofrog !

Subconsciously I had dismissed the short Ys thinking they were setrack for some reason and therefore insulfrog

Thanks for everyone's input most appreciated

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