Pecos River Brass 4-6-2 part 2

[ATSF_Ron]

Several months ago I posted about some running/shorting issues I was having with a newly acquired brass model from PRB.  After much helpful input from several TRW members, I decided to take a break from this thing.  I also was dealing with a Key 2-8-0 with similar issues and getting nowhere with either one.  I was quite frustrated.  Now it's time to get back to this baby!  These are normally very smooth runners, so I want to get it back into my operating fleet.  I believe I've narrowed it down to the drawbr-to-tender connection.  More specifically, I think there's an issue in all of the little springs/washers under the loco cab.  I have bypassed all of that and am about to try soldering a new wire from the motor directly to the tender.  I have also fashioned a new styrene drawbar.  I have clipped a power lead to one rail and another lead to the wire coming off the motor and it runs fine - but only as far as my power lead!  I think it'll be fine if I can get the motor wire soldered directly to the tender.  The first two pics show the loco and the prepped wire ready for a longer piece to attach to the tender.






The next set of pics show the tender chassis and the stainless steel or nickel plated drawbar pin.  This screws directly to the floor of the tender, picking up power. (I assume?). I think my best bet is to try to solder the wire to the top of the pin on the inside of the tender floor.  Problem is the top of said pin is just a couple mm, if that, in length.  A nice feature is the notch in the bottom front of the tender where I can run the wire from motor to tender pin. (final pic)









I'm about to fire up the soldering iron.  I'll report back on success or not!

[mmagliaro]

WAIT!!!

I would unscrew that drawbar pin from the tender, solder your wire to a thin brass or phosphor bronze washer,
and then screw the pin back in with the washer on it.  If it is a .010" thin washer, it will make no difference to
the behavior of that pin. 

It will be exceedingly difficult to solder directly to that pin because it is screwed into the tender floor,
which will absorb all the heat from your iron.  Not only will be nearly impossible to get things hot enough to make
a solder joint, but if you do, you are likely to find other parts on that tender floor falling off as they become unsoldered.
Remember this is a brass loco and everything is soldered together.

[Mike C]

  Looks like Max beat me to it .        Mike

[nickelplate759]

or even just drill and tap a hole for a small screw somewhere near the pin, and then continue with Max's suggestion - solder a wire to a washer, and use the screw to hold the washer against the frame.  You'll probably want to remove the paint under the washer for better contact.   I've used this approach to secure electrical wires to Zamac-style frames.

[ATSF_Ron]

Thanks for the very useful tips guys, but it's a done deal.  Here's what I did.  I noticed the pin wasn't screwed all the way in against the bottom of the frame, so I cinched it up tight.  That gave me a bit more sticking out on the inside of the tender floor.  I was able to solder the wire on in just a quick second or two.  No damage!  The first pic shows the wire soldered to the tender pin and ready to be attached to the motor wire.  No, I didn't leave it looking that way.  It was much more cleaned up before the final solder.

The second pic shows the loco & tender on the track but minus the bar connecting the tender to loco.  Now that it's soldered together it's a bit of a bitch to screw on.  I also did not shrink the black piece of wire shrink wrap until I knew it was running 100%, in case I need to redo anything.

It's far better than before, but there's still an issue.  She'll go maybe 5 or 6 inches and stop.  I give her a push and she does it again.  Both directions.  One thing I forgot to do which might be contributing to the problem is this: I noticed when the shell was off that the motor wire attaches to the top of the motor.  The connection looked a bit iffy, and I forgot to touch it up with fresh solder.  Also, the clearance between that connection and the inside of the UNPAINTED brass shell seems mighty close.  I was going to put some electrical tape over it but forgot that too!  I feel like I'm very close to having this bugger fixed.

[mmagliaro]

I am glad you got it to work, but I would still be dubious of how good that solder joint really is.  They will often stick like that and then just break off later, because it's hard to to make solder flow well with all that metal.  You can do a bit better if you
put a dab of flux on there before soldering - that will make a lot of heat flow quickly, and you should get a better joint that way.

The other issue is that it isn't really serviceable.  Every time that wire breaks off, you will have to resolder it to the screw on the tender floor.  I'd still undo that and use a washer, but that's up to you.

As for your other shorting problems... I don't know if you are testing this with an ammeter in the circuit, but you should.  If the engine stops and the meter is pegged, then you can be certain the problem is a short, as opposed to an open circuit.

I'd vote "definite yes" on putting some tape over the top motor terminal so it can't touch the brass boiler.

[ATSF_Ron]

Max, I'll definitely consider adding the washer to that pin.  I did use flux before soldering.  Always do!

Question:  In the pic below, what is this part of the motor on top of where the wire is soldered? (The part that the #11 blade is pointing to.) When I press on that lightly if the loco is stalled, it starts back up immediately.  It almost looks like the top of a screw that can be tightened.  I redid the solder joint and tested it before putting the shell back on.  95% improvement!  Of course, without the weight of the shell, I think the electrical connection is lacking.  Still, much better!

Time to prep dinner for the Mrs. for Valentine's.  Tri tip, sweet potato and Brussel sprouts!  I'll report back tomorrow...

[mmagliaro]

Well, then... Happy Valentine's Day to you!
That is the top brush holder.  It might unscrew or pry out (I can't remember, even though I have worked on that exact
engine and motor before).  Inside is the spring and brush.  If touching that makes it go when it stalls, you might have a broken brush or a collapsed spring in there.    But since I can see the top of the spring through the hole in your photo,
I kind of doubt that.  More likely, the top of the brush cap just isn't making good contact with the bronze lug ring that you soldered the wire to.  Try pushing the cap down to make sure it's all the way seated.    If that "fixes" it and it runs
reliably, see how it does.  You might have to remove the holder and give that contact ring a little bend before you put it all back together so it exerts some spring pressure on the brush cap.

One more thing... when you solder directly to that contact on the brush holder like that (without taking it out), you have to be QUICK.  Heat from the iron can ruin the spring or brush.  Just something to be aware of.

[peteski]

I agree with Max that most likely the brush holder cap is not in good contact with the brass ring with the wire soldered to it.  The brush holder cap has a slot in it, so it likely is a screw-in brush holder.  See if you are able to tighten it.

Also make sure that the brush holder, brass ring, and the wire are not touching the motor's metal frame. The frame is connected to the electrically-live loco chassis and if any of those items were connecting to the metal motor frame that would create a short.  The entire brush holder assembly should sit slightly proud of motor's metal frame.

[randgust]

I'm assuming the tender here only picks up on one side?  So that's why there is only one wire?

I've done conversion of the tender trucks to both sides on about every steam locomotive with a tender I've got, and that's been the silver bullet on performance for me.   I have the rebuilt Jamco 4-6-2, and I swapped the entire tender for one of Dirks (ATSFscalemodels.com) to get 12x12 end axle pickup and that was so effective I didn't need much else to fix the flaws in that one.   He has wired trucks available.

But I also got rid of the post and wiper and went to a micro two-pin plug (computer jumper style) that you can get from Ebay or other suppliers, the smaller the better.  It slips up inside the tender so you can still get it off.

I've done either hard-wire, wires to a screw connection, plugs, or something on every tender.   The wiper arm concept on a metal post just doesn't work reliably.  The very best has been the TCS 6-pin off of my Decapod project so I could bring the isolated motor, front pickups, and headlight back into the tender, as that whole project is looking down the road at DCC and sound.   That 6-pin connector is the best I've seen yet, sturdy, tiny, very soft braided wires.

If I have the choice between a flywheel and rebuilding the tender pickup, I'd pick the tender.

[ATSF_Ron]

Thanks for all that info, guys.  Max & Peteski, the brush holder doesn't appear to be loose.  Trying to screw it in yielded no movement.  I'd rather not disassemble it or pry at it.  The loco has actually been running back and forth and through turnouts without hesitation for a while now.  Randy, I have seen those tenders and trucks from ATSFmodels and have thought about replacing the brass ones with his so I get all wheel pickup in the tender.  We'll see how it goes.

Going to give the gears and worm a drop of oil and then reassemble.  I thought I had lubed it when I first opened it up some months ago, but they looked bone dry to me yesterday.

[ATSF_Ron]

Here's where things stand now.  Please pardon the ugly treatment of the hardwire from motor to tender under the cab.  After connecting it, it's obvious it needs to be shortened and tucked back up under the cab some more.  However...all shorting is SOLVED!!  It runs "nearly flawlessly" in both directions and through turnouts.  I'm stoked!

Sooo..."nearly perfectly" needs an explanation.  The loco has never done this until today, not even in a cradle on test leads.  I suspect it's something I did during the "fixing process," like possibly tweak a siderod or something.  There's a pronounced hitch or gallop as the drivers rotate.  It's not terrible but is definitely annoying.  I don't care for any hitch in a steamer, so I'll be delving into this some more.  Maybe it'll improve once I get her on the test loop for a while, but for now I'm happy.  Honestly, after my Key AC6 debacle last year, in a different post, this was by comparison a piece of cake.  Thanks to all who contributed their suggestions, advice, and experience!  Love this forum!

[mmagliaro]

Since it's gear driven on one driver only and the others are connected by the rods only, unless you bent a siderod (unlikely), it's probably something else that's binding if it didn't do this before.   Look for the usual suspects:

- Behind the crosshear (the valve slider), where the driver and crankpin whiz by there - make sure the pin isn't getting hooked on the backside of the slider assembly anywhere. 

- Make sure that valve slider is really free and loosey goosey.  It's not uncommon on a brass engine
 for those to have one little tight spot in their motion

- MAKE SURE the valve pistons can't pull all the way out of their cylinders when they are pulled back all the way during
the wheel rotation cycle.  I've seen that more than once on brass.  If that little rod pulls all the way out of the hole
in the cylinder, and then "magically" finds its way right back in on every cycle, you'll get a hitch once in a while when
it gets stuck on the way back in.  And if it ever misses and rams up against the cylinder, disaster can ensue in the form
of bent rods, so look for this.

- Wiggle all the pin/rod joints with tweezers and make sure none of them are tight.  They should all have a little wiggle in them.
- Make sure the drivers are touching/rubbing/grazing the inside of the boiler.

Brass engines are funny this way because things can more easily bend out of position from handling than on a plastic engine.

I reviewed my old repair records and found this note on one of these Pecos River engines I repaired.  You may find it
amusing:

"Left side valve slider:  Main rod would hit the lower slider guide on every rotation, causing a
bind in the motion.  File lower edge of the slider guide.  The hardest part of this was just figuring out
that it was doing it (figure out where the bind was coming from). "

[ATSF_Ron]

Thank you, Max!  You're always a fountain of N scale brass knowledge.  I'll check this in the morning.

[ATSF_Ron]

Getting back to this and the "binding Gremlin."  Max, I tried all of the things you mentioned in your last post.  Here's what I found.  There's a tiny phillips screw near the ladder mounted to the valve gear assembly.  That screw on the engineer's side was hanging on by maybe one twist.  Hence, very floppy valve gear operation and most likely the cause of the bind.  I gently tightened it up and voila!  No more Gremlin!

But...in testing on the layout I have a tender derailing issue.  It's difficult to say if this was happening before, since the shorting issue prevented me from any kind of extended operation beyond about 12 inches.  Take a look at the clearance between loco and tender in these pics.  In particular, notice the bottom of the cab roof clearance compared to the top of the front of the tender.  It's tight!






When it goes into a left hand turnout from either direction, the cab bumps into the front of the tender and the front tender truck derails every time.  Interestingly, this does NOT happen on my right hand turnouts.  It took some time to get this figured out since it is such a tiny clearance area.

Now check these pics for another possible cause of the problem.







I notice two things.  The angle of that drawbar seems like it's going in a rather steep upward direction, which I believe could be causing the derailment issue as well by exerting a force which lifts the front tender truck.  When I run the loco slowly through the turnout, that's the motion I notice.  It's upward AND sideways.  I made another drawbar from styrene a while back, but it's a royal pain trying to to get the factory screw through that thing under the loco, so I'd prefer to use the factory drawbar.  I can bend the drawbar into a straighter angle, but I'd prefer not to do that while still attached to the loco.  That may help with the possible binding connection.

The second thing is that damn ugly wire from motor wire to tender that you see under the cab.  I'd like to ditch the whole thing and go with ONE wire of the original size.  My problem is finding some!  The piece of wire I used was the smallest I can find in my area, and to me it looks too big still.  And wouldn't you know it, the joint where the wires are soldered is in plain view (heat shrink tube).  In the first pics of this thread you can see the Brawa wire I used.  It seems like something half this size would work.  I don't want to buy 5 meters of the stuff!  I just need a few inches.  I've seen things on Amazon, but I'm not sure of the size.  Does anyone know the approximate size wire used in brass loco wiring?  Thanks!