Shorts

[crisco1]

Hi,

Does anyone out there have a proven method for finding shorts on a layout using (DCC) Digitrax?  I have remove all my engines, and freight cars.  I made sure that all my leads were the same color, when I connected the leads to the buss wires.

Thanks,

Chris

[BigDaddy]

Is this an old layout with a new short or new construction?

Reversing loops?

Are there separate power districts you can isolate?

For the sake of completeness, where is your KD couper gauge?

[gregc]

crisco1

Does anyone out there have a proven method for finding shorts

divide and isolate.   Disconnect half the layout to determine which half has the short.   then divide that section in half and so on ...

of course, if you made any recent changes,  they are the most likely cause. 

[richhotrain]

Definitely divide and isolate.

Over time, experience will make the search for shorts somewhat intuitive. You get a sort of sixth sense about the nature of the short.

Rich

[hornblower]

The short could be anywhere with Digitrax.  A fairly recent operating session I attended was cancelled due to a hidden short somewhere on the layout.  The short was eventually (about a week later) tracked down to a failing UP5 panel.  I was shocked to learn that these panels not only connect to the throttle bus as with any other brand system, but also require separate power supply connections, AND connections to the track bus!  Seemed way too complicated if you're just trying to get the throttle to talk to the command station.  

[gmpullman]

I disconnected all of my UP5 panels from track power. They only illuminated "track status" LEDs. It is not needed nor required. UP5s do not require any additional power.

Only the UR 90/92s require outside power and Digitrax provides the PS14 to supply the power for these. They do not have to be wired to the track buss at all.

It is not at all complicated.

Just my experience. Dividing the layout into power districts and using an electronic circuit breaker for each power district makes troubleshooting easier.

Good Luck, Ed

[Drumguy]

Take a scap of 1x2, short enough to fit in a gondola or flat car. Paint or write "red" on one side and "black" on the other (or whatever colors you used for bus wiring). With power off, run it around the layout by hand. If at any point the red side of the 1x2 is on the black side of the bus, you've inadvertently created a reversing loop. It's remarkably easy to create a reverse loop without realizing it. im sure a lot of folks her have done it. Me at least twice.

[CGW121]

What system are you using? If you  have a 515 power supply that is probably what is causing the problem.

 

[CSX Robert]

hornblower

The short could be anywhere with Digitrax.  A fairly recent operating session I attended was cancelled due to a hidden short somewhere on the layout.  The short was eventually (about a week later) tracked down to a failing UP5 panel.  I was shocked to learn that these panels not only connect to the throttle bus as with any other brand system, but also require separate power supply connections, AND connections to the track bus!  Seemed way too complicated if you're just trying to get the throttle to talk to the command station.

As mentioned, the track connections and power supply connections are optional (and are clearly labeled as such in the manual).  The power supply can be needed on large layouts, because with enough throttles you can exceed the capacity of the command satation powered bus; however, this is also true on other systems.  For example, NCE and MRC both have power options for their throttle panels for when you have a lagre number of throttles (although with MRC you actually have to buy a different powered throttle panel).

[G Paine]

hornblower

The short was eventually (about a week later) tracked down to a failing UP5 panel.

Same thing happened to me about 6 months ago. I went nutz  looking for a short in the track before I decided to disconnect the Loconet from the Digitrax command station; then the short disappered like magic.

[rbturner]

On the very few occasions I have had trouble similar with my Digitrax outfit, a simple cleaning restored operation.

Unplug every RJ-45 connection. I use alcohol on a Q-tip to reach inside and clean the little wires of the female connector. A mascara brush also works well here and it also cleans the male connector. Use caution because the little wires inside can become dislodged. This can be repaired easily with tweezers though.

Over time, I believe, oxidation occurs in the connectors and causes goofy operation. Not necessarily a short as many people refer to nearly any electrical malady.

[Steven Otte]

Thread moved to more appropriate Forum.

[BroadwayLion]

LION does lots of trouble shooting. Him uses DC not DCC, but wire is wire if you want to check the wiring, just disconnect the DCC and test the wires.

LION uses nails for binding posts, with thousands of connections of railroad of him.

The hardest gremlin to find was the time teo nails made contact insde of the board. Still divide and Conkor. : )

Another issue can occur if you use cables such as CAT-5 and a staple or a nai peirces the insulation of two or more conductors. I found that once and just abandoned the cable and installed a new one.

ROAR

[rrinker]

hornblower

The short could be anywhere with Digitrax.  A fairly recent operating session I attended was cancelled due to a hidden short somewhere on the layout.  The short was eventually (about a week later) tracked down to a failing UP5 panel.  I was shocked to learn that these panels not only connect to the throttle bus as with any other brand system, but also require separate power supply connections, AND connections to the track bus!  Seemed way too complicated if you're just trying to get the throttle to talk to the command station.  

 

 They do not REQUIRE extra power unless you are running a lot of throttles - and that's the dirty little secret at least one manufacturer (MRC) keeps very hidden- they need the same thing! Except their panesl that have a jack for external power a 2x the price of a UP5.

 There is also no requirement to hook up the UP5 to the track bus. In some cases you can;t - if you hook up the track power and you use block detection, the block will always shoe occupied. No need to even bother hooking it up.

 If you are running a small layout with only a coupel of throttles in use, all you need to connect the UP5 with is the Loconet cable - same as all the others.

 Also, the short condition for a shorted Loconet/Railsync cable will usually be different that the short condition for the rails. The breaker won't be tripping for a Loconet short, you just won't be able to power up any throttles, or maybe a downstream bosoter won;t turn on, or output anything, because it's not getting any signal. With a track short, the throttles work fine. More divide and conquer - requires a little thought, but if the throttles act fine but the breaker keeps tripping, it s aproblem in the rail wiring. If the throttles aren't coming on, the problem is in Loconet bus. That includes throttles not coming on and/or track short at the same time. Just track short - it's not the Loconet.

 And why would the PS515 be the source of a short? It's just the power supply feeding the booster. A failed PS515 would not present as a short on the rails, it would also generally mean no power - to the rails or to the throttles. Or a system that powers up fine but shuts down or otherwise acts weird with even a light load - ie not even coming close to the 5 amp rating.

                         --Randy

 

[hornblower]

rrinker

 They do not REQUIRE extra power unless you are running a lot of throttles - and that's the dirty little secret at least one manufacturer (MRC) keeps very hidden- they need the same thing! Except their panesl that have a jack for external power a 2x the price of a UP5.

I admit to being one of those "weirdos" who bought an MRC Prodigy Advance system.  I have multiple tethered throttles plus a wireless receiver plugged into my throttle bus and everything works fine.  I didn't spend a dime on MRC manufactured throttle bus products.  I used standard Cat5 cables, jacks and wall plates I found at a local electronics store.  The throttle bus includes five (5) wall plates installed in the fascia with two RJ45 jacks per plate.  The plates are distributed around my two-car garage filling double deck layout. The only power to the throttle bus comes from the command station. Everything works perfectly.  

I was just surprised to find so many additional connections to the suspect UP5 panel when troubleshooting the malfunctioning layout. Since there was a direct connection to the track bus, it made sense that any problem with the throttle bus could also affect the track power.  I'm sure these track bus connections are meant to offer some advantages I am not familiar with, but I wouldn't want them on my own layout.

[Bayfield Transfer Railway]

I bet a bright shiny nickel you're feeding power to the frog of a solid-frog turnout.

 

[rrinker]

 Yes and my last two layouts have worked fine with Digitrax with nothing but the phone cord connected tot he UP5's - because so far I've never had more than 2 throttles plugged in. My new layout will be cabpable of handling up to maybe 6 crews, possibly more. If they all use plug in throttles, I will need power to the panels. But I will probably go wireless. MRC is exactly the same, except they bury the fact in barely a footnote in the instructions. And you need to use their special power panel, unless someone has published a schematic so that you can build your own. I don't know any system that doesn;t need this at some point once you exceed a certain number of cabs. It's not a design issue, it's basic electricity, thin phone-type wire can only handle so much current before the voltage drops, it's like the track bus in miniature because throttles draw less current than most locos - with phone wire instead of #14, the number of amps you can draw is much less before you see a few volts worth of loss. Even the vaunted for simplicity CVP system needs power distribution for the throttle network, only they centralize theirs with a panel that both injects power and converts the phone line cab bus from the command station to the coax cable that runs to the throttle plates. There is a certain number of throttles you are allowed before needing to have this component added to the system, just like everyone else.

                       --Randy

 

[richg1998]

crisco1

Hi,

Does anyone out there have a proven method for finding shorts on a layout using (DCC) Digitrax?  I have remove all my engines, and freight cars.  I made sure that all my leads were the same color, when I connected the leads to the buss wires.

Thanks,

Chris

 

I assume the layout was working fine. What did you do just before you realized you had a short.

Rich

[TBat55]

Wires for sure, but don't forget the rail gaps.  Expansion & contractions not a big concern if you fill the gaps with styrene.

[Anonymous]

Do you have a reversing loop?

[richhotrain]

Chris???

Earth to Chris !!!

Are you there?