BLI F3 and F7

[Carolina Northern]

I'd ask anyone with some electical knowledge to think of the result when you run current through two dissimilar metals while in loose (relitively) contact.
That is in effect what is happening when you use a rail joiner to send the signal through through the track. This is more pronounced with an AC signal - which DCC resembles.
Eventually, you're going to have trouble - usually mysterious intermittents.
Just prevent them by doing it right.

[NorsemanJack]

I'd ask anyone with some electical knowledge to think of the result when you run current through two dissimilar metals while in loose (relitively) contact.
That is in effect what is happening when you use a rail joiner to send the signal through through the track. This is more pronounced with an AC signal - which DCC resembles.
Eventually, you're going to have trouble - usually mysterious intermittents.
Just prevent them by doing it right.

Which dissimilar metals are you referring to?  I was speaking of Unitrack, and I believe that both rail and (current design) joiner are nickel silver.  Also, I don't use DCC, so I can't speak to the issues in that realm.  I do know that we have many users of Unitrack w/DCC and I've never heard of a systemic problem that results from not soldering a feeder to every rail.  Certainly, I accept that lesser brands of track (with poorer quality metals) may have some problems; but then those extra feeders may just be band-aiding a root cause.

Any Unitrack users out there that solder a feeder to every rail?

[RBrodzinsky]

Yep, I have soldered feeders to (almost) every piece of Unitrack on the JACALAR. I actually had a failure, early on, where one rail on a section was dead. Bob (PowerSteamGuy) helped me through it, and that was when I learned never to rely on the unijoiner for track that was being permanently laid, with scenery and ballast. Never had a problem with relying on the unijoiner for quick test and short runs of track, though. The difference is the physical action of sliding the tracks together every time versus a permanent (going on 9 years) layout.

For the issue at hand, lack of feeders might have caused voltage and signal drops, but that would then have been with all the command stations. A properly running Zephyr (DCS50 or DCS51) or a PowerCab will run a single sound loco (or even 5 or 6) without an issue. But, I am with Peteski on this, the behavior doesn’t quite make sense.

[daniel_leavitt2000]

Cgw, how are you measuring the temperatures with your set-up?  If you are looking for an infared image of hot components through the loco shell and bubble wrap, how confident are you that you can detect a single SMD on the decoder board that is overheating?

One of the other things that I note in your experiments is that you seem to be having the wonky behavior right away when on the systems that you think cause it.  But, Spookshow's experiences seem to indicate that it takes a while for this behavior to develop, at least in a new locomotive.  His review says they worked great right out of the box when not pulling anything, then talks about how bad it gets after 15 hours of running.  It sounds like at least he thinks it has something to do with the gear mesh getting out-of-wack and the decoder's response to that.

So far, my own minor testing has been with a Power Cab feeding 2 places on a Kato Unitrak loop with 142.5" of track. Track is 15" radius with 15° 19" radius "easements" and straight sections 22" long. Feeds are on the opposite ends of the straight sections.  There are no isolation joiners in the track, so it is electrically a single loop, not one or two straight sections.  That has never caused a noticeable problem, so far.

All of my new BLI F-7 units have run very smoothly right out of the box, but under no load, so far.  All have exhibited sounds that seem to indicate throttle-up and throttle-down actions with no actual throttle inputs.  However, when I turn off the sound and watch the locos carefully, there is no apparent actual changes in speed.  The throttle-up and down sound effects tend to occur at about the same places in the loop, but not every time the locomotives pass those places.  Current draw as indicated on the Power Cab seems to be fluctuating between about 0.08 and 0.12 amp in a manner that does not appear to correlate with the sound effect changes.

Are these occurring on a curve? I wonder if this could be a intermittent short in the trucks. Or the sloppy gears temporarily freezing or increasing friction enough to spike the motor's current draw, triggering BEMF with the sound file being linked to that.

I almost WANT to get one now, just to experiment with.

[Carolina Northern]

Not to take this off track - the BLI problem - I looked into this first because of the problems John Sing had on his layout. It was small - 4X4 and after about three years he had problems with voltage loss. He documented it and the fix, right here on Railwaire and on the old Atlas board.
The problem makes complete sense if you look at the electrical side of it. The Unitrack and Unijoiners are both "nickel silver", but are different formulas. Nickel Silver is a very loose term. The formula used for the track would not form into the  joiners that well.
As for do people solder the every piece of Unitrack - I've done it on every layout. The long lamented Carolina Northern lasted 12 years with no electrical problems.
Remember, the effect is greater with moisture - humidity or track cleaning fluids.
The old often stated rule of jumper every three feet ( I was a model railroader back when that was first becoming popular) - comes from HO at the time HO flex was three feet long - one jumper set every three feet.

Last word then back to the real subject - Never rely on two pieces of metal lightly touching to conduct over an extended period of time.

[NorsemanJack]

Not to take this off track - the BLI problem - I looked into this first because of the problems John Sing had on his layout. It was small - 4X4 and after about three years he had problems with voltage loss. He documented it and the fix, right here on Railwaire and on the old Atlas board.
The problem makes complete sense if you look at the electrical side of it. The Unitrack and Unijoiners are both "nickel silver", but are different formulas. Nickel Silver is a very loose term. The formula used for the track would not form into the  joiners that well.
As for do people solder the every piece of Unitrack - I've done it on every layout. The long lamented Carolina Northern lasted 12 years with no electrical problems.
Remember, the effect is greater with moisture - humidity or track cleaning fluids.
The old often stated rule of jumper every three feet ( I was a model railroader back when that was first becoming popular) - comes from HO at the time HO flex was three feet long - one jumper set every three feet.

Last word then back to the real subject - Never rely on two pieces of metal lightly touching to conduct over an extended period of time.

Fair enough.  I assume you're poking at the problem with galvanic corrosion, which IIRC requires not only dissimilar metals but also an electrolyte (likely why you mentioned moisture as compounding the "problem.)"  That said, if the price of admission for Unitrack was really to solder a feeder to every rail, then I would just use code 55 flex (I have before, and I did solder a feeder to every rail).  I currently have a "semi permanent" Unitrack layout, but none of the track is ballasted or secured, so maintenance of any bad players would be very simple; likely much less effort than all those feeders on the front end.  It's simple enough to use a multimeter to confirm suspected voltage drops. 

[R L Smith]

My last layout had about 50 feet of double track Unitrak with Kato track feeders about every 6-8 feet.  The only continuity problem I ever had was due to paint getting into a joiner when I was "improving the appearance ".

Lenz DCC and a relatively stable temp and humidity situation.

I agree with Norseman, soldering Kato track is not necessary and kind of defeats the primary reason for using it: fast, nearly bulletproof track.

YMMV

Ron

[NorsemanJack]

My last layout had about 50 feet of double track Unitrak with Kato track feeders about every 6-8 feet.  The only continuity problem I ever had was due to paint getting into a joiner when I was "improving the appearance ".

Lenz DCC and a relatively stable temp and humidity situation.

I agree with Norseman, soldering Kato track is not necessary and kind of defeats the primary reason for using it: fast, nearly bulletproof track.

YMMV

Ron

Thanks Ron.  My current Unitrack shelf layout runs about 40 feet for each of the four "loops," and I have Kato feeders in six locations; so like you about one every 6 - 7 feet.  All Kato double track (I really like their larger radius super elevated curves).

I don't currently run DCC, so can't speak to experiences some are having with the BLI locomotives.  If they were due to track continuity problems, then we would expect them to show up on other brands/models of DCC equipment as well.  A person's layout shouldn't require 100% perfection of track electrical performance for the equipment to run reliably.  If it's an incompatibility of BLI decoder and DCC system, then we can't blame the track.  From all of the reports (on at least three forums now), it sounds like the BLI decoders may be to blame.  Of course, this could be like the old Atlas code 55 spike problem, where the new product that is causing problems technically meets the specs and it's the rolling stock that has been non-conforming for years.  I suspect that somebody will nail this down a bit more specifically before all is said and done.

[peteski]

This discussion seems to be getting way out of hand.
None of the connectivity issues being thrown into the mix here could cause the loco's behavior described here: regular and cyclical slowdown to a stop, then back to the previous speed.   I also posted few comments earlier where I doubt that few other possible reasons for the problem also seem unlikely to me.

[Maletrain]

Agree that it is time to get this thread back to looking for some real solution.

It would be helpful if people who have seen the "wonkiness" and then put shims on the idler gears can tell us if that had any beneficial effect. 

On thing that I noticed while looking at the tech manual to see if I could turn off the "Rolling Thunder" transmitter (couldn't find that) was "Fatal Ovrecurrent Configuration" and "Fatal Overcurrent Sensitivity", CVs 176 & 177.  They seem to be associated with BEMF and protection against short circuits and/or locked motors (or drive trains).  Reading that material did not give me a good idea about how this might tie into our slowing/stopping/restarting/speeding-up issue.  But, the documentation is meager, and there may be some "undocumented features" (AKA "bugs") associated with that.  It just occurs to me that a feature set-up to block decoder damage from a locked motor might interact with some gear and/or worm mesh issues to cause this problem to occur after some use and intermittently.

Hopefully somebody with more knowledge and experience than I have can look into this?

[greenwizard88]

I have sent the digitrax dcs51 unit off for repair that was the worst offender .   I will know in about three weeks what they find out.      I am begging to wonder if the unit could not keep up with the current load of the sound decoder.?   When you watched the loco go roundy it would come up to speed slow down stop. then the engine would come back up to speed and then repeat. This would go on and on till I shut I down.  Very odd behavior.    could not duplicate it with the other digitrax units.

I always wanted to get one of the pricom packet testers but I promised the significant other that I would cut back on the hobby purchases. (after I get ;my bli t1's)

I have a problem child ES44, that I've grown too familiar with -- to the point that I'm sitting on a café and I'll happily tell you which CVs are causing this issue. CV112-CV119. They regulate the BEMF derivative, integral, and (IIRC) CV 120 is break sampling. If you mess with them, you can end up with an engine that doesn't run at all, or speeds up and slows down as you described. It's got nothing to do with the DCS51 (although that's what I use too) unless the single N scale engine is using more power than a few HO sound locos would, or the Paragon3 can't handle the "high" 14 volts on the rail... N scale Digitrax, TCS, and ESU decoders all work fine for me.

Using JMRI, I somehow managed to get function 4 to be the break function. Enabling it would also cause the engine's speed to alternative like a sine curve. I wish those CVs were better documented, I may call BLI at some point to try and figure it out.

Another thing I noticed is that the Paragon3 prime mover notching is based off of BEMF, not just speed step, so when my problem child ES44 goes over a specific #6 switch, and slows down, I hear it notch as well. Then it goes back to full speed and the previous notch. This isn't the DCS51 randomly sending a slower speed step packet at the same location on my layout every time.

[drbnc]

It would be helpful if people who have seen the "wonkiness" and then put shims on the idler gears can tell us if that had any beneficial effect.

Shims.  See my issues way back in this meandering thread.    Yes, shims worked for me.  But I think the main issue I had was a front gear tower that was not meshing with the worm properly.  That happened to be coincidentally fixed at the same time I cut some shims, since I had to pull the trucks and reseat them.  Fix _two_ things, which was the cause of the "jackhammer" sound I had with my very first run of an F7 set? 

By the way, I had a *great* experience with their tech support.  They offered to replace _both_ sets I have (F3 and F7 A/B) with bench-tested units.  I declined, said I would just run them till the wheels fall-off, then contact them for support.

The A units are too light.  I'm in process of adding weight via tungsten putty and rods.  I'm now of the mind that it's either good sound or heavy weight.  I know you can extract more traction from a Kato or IM.  I own multiples of those as well.  These are what they are.  Vote/buy accordingly.  Yes, the grilles are wrong on the F3's.  Mine are Black Widows, so I can't easily see the grilles.  The rest of you need to decide with your wallets.

I'm not having the DCC issue that Spookshow saw.  That's _just me_, two data points (F3/F7). I use NCE PowerCabs with an SB5.  You mileage may vary. My system is unique to me.

[Roger Holmes]

I ran my two powered Milwaukee Road F7A's for half an hour last night with no issues.  I spaced them a foot apart and they maintained good speed matching.  Haven't pulled a load yet.  My layout has zero grades.  I have a digital scale speed speedometer and they ran 7 mph in speed step one.  I use a Digitrax Radio Super Chief ( the pre-duplex version).

Lighting effects are excellent.  Factory sound level is way too loud even for my "lifetime as a drummer" ears.  Horn has a subtle reverb at the end of each blast--very cool.

As soon as I get time I will play with the volume CV's, consist them and add the dummy B plus a train.

[ntrainman]

Well I received my BLI Northern Pacific F7s yesterday. I'm not sure what all the fuss is about for these engines. My F7 A units run great and there is not a mess of wires under the hood. I see two on top and the 4 from the trucks to the board (you see about 1/4" of the wires). The lights up front are done via pc board and work great. Overall I love my engines and they operate flawlessly. 

[Maletrain]

The "fuss" about the F-7s is just that they may not continue to run fine, given the loose gear axles and Spookshow's experience when running them for a while.  The rest of the "fuss" is mostly cosmetic, and largely about the backwards grills on the F-3s.