NCE PowerCab: A Quick Look review - PLUS Resolving issues

[tstage]

Derrick,

I don't mind the fact that the Power Cab is light in weight. It's probably lighter than your Pro Cab because they were able to shrink things down by using smaller parts and boards. Derrick, except for the difference in weight issue you mentioned, It's supposed to be exactly the same.

If you are looking for place to put your Power Cab when not in use, Litchfield Station has holders that will attach to the side of your layout bench that only sticks out maybe 2" or so. Terry (scubaterry) and his neighbor made several homemade versions of the same style out of parts that he got from Home Depot. According to Terry, they came to about $1 a piece.

Tom

[sledgehammer]

What did you do with your main board of you powercab. Do you have it sitting somewhere or did you attach it to your lay out.

I was just on terry site and looked at them. I think there perfect holders and Im going to the local hardware store and get some of the corner pieces he used. Igot some of the protective covering ( black fiber) off a new couch we bought. Im going to line the inside with that

[tstage]

QUOTE: Originally posted by rrinker

Good job of isolating the problem Tom. One thing to keep in mind about the wheel position is that if there is a spot in the frog where something can bridge the gap between opposite polarity rails, it doesn't have to be wheels on the loco that are connected to power pickups. Or it could be a combination of wheels on the same side.
On a different issue - just to avoid a potential OOPS, I would recommend you use a DPDT toggle instead of the Atlas Connector to switch your program track - the way you have it, you COULD accidently leave the main powered and program all locos.

--Randy

Thanks, Randy. I actually did consider the DPDT toggle, but there wasn't a pretty way to install it without having to hog out a huge hole in my layout bench. The Atlas Connect is nice from the stand point that it's low profile and held in by two screws. I'm aware that the "Oops" factor is a possibility.

I'll keep working on the switch/shorting issue and report back on anything definite. Thanks for the pointers to watch out for on the wheels. [:)]

Tom

[tstage]

Derrick,

Right now I just lay mine on top because I use it as a "tethered" walkaround. I do like the holders though and may have to look into making one myself.

Derrick, be careful about the type of foam you put in the bottom of the holder. Some can degrade over time and leave a real mess. Even if you do use one, don't glue it in but just cut it to shape so that it just fits down inside the slot. If it does go bad or degrades, you can just pull it out and replace it with another one.

[Oops. [:I] Sorry, Derrick. Reread that you plan on using the black liner from your sofa to line the inside of the slot with.]

Tom

[simon1966]

Tom,

I would have thought that you would have different results from the 2 potential problems.

If the track joiners are the only conduction path for power to the turnout (ie no feeders soldered to the turnout) then a loose joiner would result in the turnout simply being dead. The loco would stop, but the PowerCab would not be impacted as there is no short, just simply a dead track section.

On the otherhand, if the stall is as a result of a short, the PowerCab should cycle into its short protection mode.

So in scenario 2 and 3 above, did the PowerCab go into short protection mode? If not, then in these tests there was not a short, just a section of track not getting power to the loco.

If it did go into short mode, then Randy has probably nailed it in that the short may be between wheels on the same side of the loco.

Since not all turnouts have the same result, then I would take the path of least resistance and swap out the turnout!

[fwright]

Tom

I remember articles in MR sometime in the '60s about problems with shorting on Atlas turnouts. Snap switches in particular tend to have wider than NMRA standard flangeways at the guard rails. This lets a wheel at the frog be hard against the frog (or in worst case, pick the frog). At the same time, the plastic insulation covering the tips of the 2 frog rails (which are of opposite polarity) gets a little worn. Then a metal wheel hard over against the frog just happens to make contact with the wide part of the tread and the other frog rail - and voila - short circuit.

The '60s fix was to renew the insulation where the 2 frog rails were very close with nail polish. You might try this as a temporary measure as part of a test. a more permanent fix might include both the insulation repair - perhaps a thin application of expoxy - and adding a strip of stryene on the outside of the guard rail to narrow the flangeway (assuming it is slightly out of spec). Last, there's a good chance the most commonly offending wheel set is gauged slightly wide.

FWIW, I have read of similar problems with both the guard rails and frog shorting on Peco Insulfrog turnouts. Not necessarily common, but it has happened with both makes of insulated frog turnouts.

Hope this helps.
Fred W

[jfugate]

Tom:

Great bit of debugging. The fact rotating the turnout 180 degrees makes a difference makes perfect sense, actually.

There is a cardinal rule in feeding power to turnouts -- always feed from the point end to avoid shorting issues.

When you rotate the turnout and things work great, you are probably now feeding the turnout from the point end, and life is great. If this is true, then you should be able rotate the turnout back the way it should go, and gap the inside rail on the straight route just past the frog (or just leave out the rail joiner and make sure there is a gap so the rails don't touch) .

If my theory is right, then having gapped the rails just past the frog, your loco won't run at all through the turnout since it now won't be getting any power. You can then add power feeders from the point end, make sure the rails just past the frog are gapped, and then it should run through the turnout fine.

At least that's what it sounds like without seeing it for myself and just reading into what your text is trying to say.

The fact rotating the turnout made the problem go away suggests very strongly you need some gaps past the frog and new feeders on the points end of this turnout -- then you will be feeding it correctly from the points end.

[tstage]

QUOTE: Originally posted by simon1966

Tom,

So in scenario 2 and 3 above, did the PowerCab go into short protection mode? If not, then in these tests there was not a short, just a section of track not getting power to the loco.

If it did go into short mode, then Randy has probably nailed it in that the short may be between wheels on the same side of the loco.

Since not all turnouts have the same result, then I would take the path of least resistance and swap out the turnout!

Simon,

Yes, in Scenario's #2 & #3, the Power Cab shut down and reset again. I agree about swapping out the turnout. I was eventually going to replace the Atlas "Snap" turnouts for some #4s or #6s. This may be the impetus to do that.

Tom

[tstage]

Joe,

Thanks for the info. [:)] However, in all the scenarios EXCEPT #4, the track feeders were on the point side of the turnout. [sigh] Doncha just love problem solving. [:D]

Tom

[Stevert]

QUOTE: Originally posted by tstage

Anyhow, any input or observations or further suggestions you might have are greatly appreciated. Thanks for wading through this somewhat long "dissertation".

Tom

Simon1966 hit the nail on the head with his earlier post that included the picture of his Peco turnout. Based on the results of your various scenarios, I'm fairly certain that you're shorting to the diverging rails.

Either a wheelset is out of gauge or has too much sideplay, or the tolerances/clearances in the turnout are too generous.

Repeat Scenarios 2, 3, and 5, but use electrical tape to cover the diverging rails at the places simon1966 labeled in the picture he posted. My guess is that the problem goes away.

The reason it doesn't happen in Scenario #4 is that the dynamics are different depending on whether you're pushing/pulling through the turnout, and whether it diverges to the left/right.

For example, pushing the tender may **** the forward axle on one of it's trucks to the right, causing the wheel tread to bridge the rails and cause a short at the frog. Pull the tender, or have the frog on the opposite side, and the short doesn't occur.

P.S. Very nice job of laying out and documenting all the various possibilities and your results! [tup]

Steve

[tstage]

Steve,

I'll look into that. Thanks! [:)]

Tom

[tstage]

They say that persistence pays off. Well, in this case they are right.

First off, I'd like to thank everyone who has contributed to the latter part of this thread dealing with the shorting problem that I've been experiencing with my BLI Mike. After reading and rereading the comments and suggestions on page 5, I decided to go back downstairs this evening and see if I couldn't come up with anything more definitive - or at least to verify one or more of the suggestions to the probable cause for the shorting.

I ran the Mike on my make shift test track that I used for my experiments last night. Nothing had change: The Power Cab shut down and reset at the same exact place it had the prior night before.

Steve and others had suggested that maybe the problem lie in the wheels of the tender shorting to the diverging tracks on the turnout. Below is a picture of the problem turnout:



The next picture, although somewhat dark, is EXACTLY where the short happens:



Seems the wheels of the tender straddle the frog evenly. If I leave it in this position, the PowerCab will continually cycle off and on until I move it off the short.

Just to confirm that the tender might be the problem, I removed the tender from the locomotive and rolled it over the turnout by itself. Sure enough, every time the tender reached the location pictured above, the Power Cab shut down and reset.

Next, to confirm whether the locomotive had any part in this charade, I pushed it by itself back and forth over the same turnout. Nothing happened. Ahhhh, so the tender IS the source of the problem. Okaaaaay. We're making progress. [:)][tup]

Returning to the tender again, I rolled the tender through the turnout backwards and forwards. On each pass, I'd press the tender wheels on one side of the rails or the other to see if that made any difference in the shorting. It didn't.

I then got out my trusty NMRA gauge to check whether or not the tender wheels were out of gauge. Nope. Each of the wheel flanges fit right into the small groove of the gauge like there are supposed to. (This was the first time I had a chance to use it. [:)] )

After a call from my dear wife, who is away in Tucson taking care of her (our) mom, I came back at it and reflected what I had done so far. I picked up the tender again and moved the trucks from side to side. I put the tender back down on the track and rolled it back and forth. I thought to myself, "Hmm, the tender doesn't seem to roll very freely", so I picked th it back up to take a look at the trucks again.

It was at this point that I noticed (or actually "re"noticed) that there were tension springs and screws that held the trucks and tender pickups to the bottom of the tender.



Since it seemed to roll somewhat stiff, why not loosen the tension spring screw to free it up a bit. A half a turn with the screwdriver and the truck came right off in my hand. "Well, that's not good.", I mumbled to myself, so I tightened both screws all the way down then backed them up a full turn.

Returning the tender to the track again, I noticed little difference in the roll of the tender over the turnout,

BUT...

[:O]
the shorting problem had mysteriously disappeared.
[:O]

I hooked the tender back up to the locomotive again. The Mike ran through the problem turnout on my test track without incident. I then put it on the main and it made the "big loop" - without even skipping a beat. [^]

So, it appears that there was indeed too much play or movement in the tender trucks, even though I really couldn't feel a difference whether the trucks were tight or loose. And, sadly, there isn't really an appropriate smiley face for such a monumental occasion as this. I was think along the lines of exploding fireworks or a "Toot, Toot" from a rabid-looking train engineer. (Bergie, can we work on something?)

Anyhow, sorry to be so long-winded. I wanted to give you the good news but also wanted to let you know how I arrived at this point. Thanks for hanging in there with me throughout this saga. [:D] My hope is that this "brief exercise in problem solving" will help someone else out, too.

Tom

[simon1966]

Tom, this is really interesting. Just to add to the saga a little bit. My BLI Mike had a terrible shorting problem due to the tender. It became a dead short as soon as it was on the track. The tender chassis of a BLI Mike is metal. The conducting wheelsets are supposed to be isolated from the chassis by 2 small rectangular pieces of plastic. The screw that holds the truck passes thru this plastic, thru a hole in the tender chassis and into its mounting hardware that is attatched to the internal wiring. The thing is that the screw and the metal chassis can touch as the plastic insulator does not provide protection as the screw goes thru the larger metal hole in the chassis. The isolation here is dependent on positioning and space. In my situation it was just touching and shorting in rather dramatic fasion with sparks at the draw bar connetion of the loco. I wonder if in your case it was very close, fine in all other parts of the track, but just twisted enough to touch in this location? Anyway, keep this in mind as it is feasible that the short could come back as things move over time. Great job finding the problem.

[rrinker]

It almost sounds line one truck was reversed - however, if that was the case, it would have shorted ANYWHERE. One truck picks up from the left rail and the other from the right rail - if you look carefully at the wheelsets you should see that one set is insulated on one side tha the other set has the insulation on the opposite side. That being said, the only way all 4 wheels ont he side spannign the frog in the second picture would be 'connected' is through the locomotive which picks up from both sides, twoof the wires in the connector between the loco and tender carry the power back and tie to the appropriate truck pickup on the circuit board in the tender. But since you got the shorting with just the tender - this wasn't happening.
The only other thing I can think of is maybe the screws were touching the circuit board or speaker frame or something like that, but again that should cause a short anywhere, not just when spanning a frog.

--Randy

[tstage]

I did get one short after I put the Mike back on the track - this time as the Mike was going into (actually coming out of) the curved portion of the turnout onto the mainline. (I think one of the wheels on the tender was slightly off that caused the short.) I checked all the wheels to make sure they were on the track, ran the Mike backward and forward through the turnout, then proceeded to run the Mike around the layout a few times without any further issues.

Randy, once again, I'm always grateful for your warehouse of electronic knowledge, explanations, and input. Simon, did you ever fix the shorting problem you described on your BLI Mike? What did you end up doing? Sparks off the draw bar is NOT a good thing. [:O]

Tom

[simon1966]

QUOTE: Originally posted by tstage
Simon, did you ever fix the shorting problem you described on your BLI Mike? What did you end up doing? Sparks off the draw bar is NOT a good thing. [:O]

Tom

I sure did. I took the tender apart which and removed the decoder and sound unit. I still had the short with everything removed, which led me to investigate the truck mounting. In the end removing them and re-installing them to ensure that the screw was not touching the frame was all that was needed. In other words, what you did[:D]

[Stevert]

QUOTE: Originally posted by simon1966

The screw that holds the truck passes thru this plastic, thru a hole in the tender chassis and into its mounting hardware that is attatched to the internal wiring. The thing is that the screw and the metal chassis can touch as the plastic insulator does not provide protection as the screw goes thru the larger metal hole in the chassis. The isolation here is dependent on positioning and space.

So a metal screw is required to conduct the current up to that internal wiring? If that's the case, nylon screws aren't an option. Is there a way to insulate the portion of the screw that makes contact with the frame? Maybe a short piece of styrene tubing, or even some nail polish on the threads?

Steve

[tstage]

Steve,

Hmm. Loctite might have a product to do that.

Tom

[jfugate]

Tom:

Is the bottom of the tender metal, and if the wheel flanges from the wrong rail happens to touch the underside of the tender, do you get a short?

If that's the case, you might put some pieces of scotch transparent tape on the underside of the tender in the offending areas. This way, even if the trucks happen touch the bottom of the tender, you won't get any shorts.

As you can see, shorts on a DCC layout are annoying, especially if they get back to the booster, because then it will go through a power cycle, which is annoying. By using Tony's power shields or the 1156 auto tail light trick, you can "catch" the short prior to the booster.

For the ultimate in short-proofing a DCC layout, create train length blocks, each with a "short catcher" on the block and then all the other trains in the power district will keep running! I demo this on a video here:



http://mymemoirs.net/preview.php

[tstage]

For those of you interested, I received my NCE CAB-04p throttle and UTP panel in the mail today from Litchfield Station. Now I can plug it into either the auxillary RJ-12 connector of the Power panel or the UTP panel and use it as an extra throttle.

I'll be reporting back on how it works (along) with Power Cab, as soon as I get a chance.

Tom

[jimmylow]

Can PowerCab run on DC mode? I am referring to page 41 of the manual which allows setting for DC (Analog) mode?

I read that it can't but the manual says "yes". Pls confirm

 

Jimmy
Kuala Lumpur, Malaysia

[rrinker]

No, none of the NCE systems can run a DC loco. The referenced information is for programming a decoder to allow it to operate on DC.

--Randy