Constant short with Lenz 100 - help!

[Davek]

Hello,

 

Having finally laid all my N gauge track with droppers and isolated fishplates on the frogs of live points (the same system I used on my OO layouts) I spent three hours today wiring it all up. I found when I attached the Lenz 100 system to the bus it found a short circuit. I have visually checked all connections, all fishplates and made sure there was no possible obstructions but the short continues. If I disconnect one of the bus wires it is fine but attach the other and it shorts again.

 

I am now at my wits end and am considering having a professional look at the layout as this is now beyond me. Does anyone know who may be able to help or can off some advice. I am in Southampton.

 

Thanks,

Dave

[Davek]

Thanks for the repyl. Yes, both bus wires (one +, one -) are different colours, to match the red/black on the droppers, to avoid any confusion. Once I'm back from another fortnight working away, I best learn how to use a meter!

[Edwin_m]

Remember if you disconnect half the bus etc the rails may still be connecting the rest of the layout electrically, and if so the short will not disappear.  If you are able to separate your baseboards then each one can be checked individually to locate the problem to one of them. 

[Davek]

It's a single board layout with two loops and sidings.

I just tried the two power buses and one wire, to the first dropper and that created a short - but there is no reason for it to do so as far as I can tell. I really hate electronics and am begining to feel that building a new layout was a big mistake.

[beast66606]

Post some photos and/or a wiring diagram - of what you have, not what you think you have. That exercise alone may reveal the problem.

 

The electronics are irrelevant btw.

[PaulCheffus]

It's a single board layout with two loops and sidings.

I just tried the two power buses and one wire, to the first dropper and that created a short - but there is no reason for it to do so as far as I can tell. I really hate electronics and am begining to feel that building a new layout was a big mistake.

Hi

 

Not much good now but I always wire a small section, test, then wire the next bit that way I know where the issue is if I get one.

 

Cheers

 

Paul

[250BOB]

Perhaps first you could disconnect the track in a few places to essentially make two separate electrical halves of track.

Then try applying the bus just to one half.......see if the fault is there.  If not try the other half, to confirm the fault is there.  At least now you are only looking at one half of your layout for the fault.

 

You can then split the faulty track half, in half again......narrowing down the search area again.

 

Have you ensured all your insulated joiners are fitted in the correct places......check, check and check again and again.....it could be a really obvious simple mistake that you are just overlooking.??

 

Bob

[Rammstein2609]

Are you using Peco Code 55 by any chance?  I understand that range is all live frog points and gave me problems several years ago before I jumped to 2fs.  There is a modification detailed in the Peco instructions to allow separate switching of the frog, this involves removing the jumper wire under the frog and switch blades.  If a little part of this is left in place could that be causing a short on the frog?

 

Cheers

 

Martin

[PaulCheffus]

Are you using Peco Code 55 by any chance?  I understand that range is all live frog points and gave me problems several years ago before I jumped to 2fs.  There is a modification detailed in the Peco instructions to allow separate switching of the frog, this involves removing the jumper wire under the frog and switch blades.  If a little part of this is left in place could that be causing a short on the frog?

 

Cheers

 

Martin

Hi

 

I use Peco code 55 points and have not needed to modify then to switch the frogs.

 

Cheers

 

Paul

[Edwin_m]

The Code 55 I have used has no such modification (it's a few years since I bought one but I haven't heard of any changes since).  I believe it is possible for their 00 gauge points but to do this in N would involve cutting the rails. 

 

If all the insulated joiners are correct then the next thing to try is the frog wiring if you have it.  If the rails aren't disconnected as above then having one of these the wrong way round would be an immediate short.  If that doesn't work then it may be a question of disconnecting the droppers one by one from the bus, checking each time if the fault has disappeared.  Invariably however it will be almost the last one you try...

[10000]

Procedure I used on a friend's 'N' layout was as follows (turned out he had 3 problems).

 

Put a slip of paper between all points blade and stock rail, so that the frogs were not powered. (He had no switch operation of the frog only the blades)  Check for short - still there checked all droppers and found one reversed. Fixed short gone.

 

But to be on the safe side removed slips of paper one at a time checking for short. First short that appeared was a missing insulted joiner.  The second one that showed up was an  insulted joiner crushed in the joint by expanding track. Fixed that and everything was OK.

[Phil S]

1/ This problem highlights the desirablility of a/ having a meter handy at all times when wiring, but also, the desirability of 'break' sections to sub-divide the laout into smaller sections DURING FAULT_FINDING.

This is easier where a layout is over multiple boards - in the worst case scenario - separating each board (and connecting wires) isolates any problem to a single board (or 'module')

 

If the dropper wires can be separated from the bus easily, then they can be re-checked with a meter, for continuity with the correct rail (and lack-of-continuity with the other rail) - in case they got transposed when diving beneath the layout

 

Otherwise, to avoid starting the wiirng (and isolating fishplates) again, you ma find you need to remove some sections of plain track, to locate the fault.

On LOW RESISITANCE range (as opposed to Continuity with a Beep)  you may be able to locate the 'SHORT' by finding which way along the track has the lowest resistance ..... I last did this when I put a metal-clad battery down on the nearest piece of track after a derailment occured elsewhere.....  It took me some time to find the cause was NOT the derailment (any more).

[Davek]

Thanks for everyone's feedback, most helpful. As luck would have it a had a group of mates round and one rund N gauge and is an electrian, so we had a quick look over the layou and after a bit of trial and error he discovered an erro with one of the isolated fishplate. I swapped it over and everything worked fine! Amazing what one small thing can affect a whole layout. Pleased now and let stressed, it means I can get on an enjoy the layout which is my first foray into n gauge.

[250BOB]

Thanks for everyone's feedback, most helpful. As luck would have it a had a group of mates round and one rund N gauge and is an electrian, so we had a quick look over the layou and after a bit of trial and error he discovered an erro with one of the isolated fishplate. I swapped it over and everything worked fine! Amazing what one small thing can affect a whole layout. Pleased now and let stressed, it means I can get on an enjoy the layout which is my first foray into n gauge.

 

Hi Dave,

We have all made that mistake..............thats why it was one of the suggestions for you to check.  

Glad its sorted.

Bob

[BoD]

Hi Dave,

We have all made that mistake..............

At least you hadn't done what I once did .......

 

.... spend half an hour scratching about under the layout only to find a pair of long nose pliers lying across the track.

 

Well they were in a far flung corner of the layout. At least that's my excuse anyway.