Pecos River Brass 4-6-2 part 2

[peteski]

I'll chime in here. Can't you just unhook the drawbar from the post on the loco's cab floor, then straighten the drawbar?

As for wire, thin decoder wire is readily available from online sources like Streamlined Backshop or others.  It is sold in fairly short lengths (perfect for hobbyists).  I have used wire from TCS, ZIMO, ESU, and Brawa.  They are all thin and flexible. 

Here is a link to some black wire: https://sbs4dcc.com/products/esu-51942-36awg-decoder-wire-10m-black.html 10 meters (~30) for less than $6. Lifetime supply for a tinkerer.  If that is still a bit much, PM me your address and I'll mail you a piece of black decoder wire.

[mmagliaro]

Yeah, I don't see the complication with just taking out that screw and spring, removing the drawbar, and bending it straight again.
Be wary there.   Brass is weird and sometimes they "fix" things with ad hoc solutions.  You might find that when that drawbar is
straight, the tender pin has a tendency to pop out of it sometimes.  So you might want to straighten it, but not make it completely straight.

If you think about the angle, yes, straightening the drawbar will get you a little more distance between the engine and the tender, but not much.  Brass is notorious for having close clearances that are prototypically accurate, but impractical for model layouts.  Cab->tender
distance is one of those things.  If it were me, I'd just start with some heavy strip brass, a pin vise, little files, and lots of patience,
and make a whole new longer drawbar.  They are not easy to make, but you probably realize that.

[ATSF_Ron]

Peteski, yes I can simply remove the drawbar. But “simply” isn’t a word that pertains to this loco,
Lol! To do that I have to pull the shell and undo a nut at the top of said screw. That’s the easy part. It took me the better part of 45 mins to get the nut back on each time I did it.  And I’ve done it countless times trying to fix this problem. There’s maybe one full turn of the screw before it stops turning with the nut on. Trust me, it’s tiny and a total pain in the arse!

It’ll get done but not without a strong adult beverage and a lot of patience (right Max? 😁). Peteski, thx for those links on the wire. I’ll check that out.  Working on these brass steamers is definitely not for wimps! Lol!

[ATSF_Ron]

Max, there are two PRB N scale steamers on eBay. One is a Pacific and the other is a Hudson. The Pacific has the upward slanting drawbar like mine. The Hudson’s appears to be nearly horizontal. Interesting. Like you said, maybe it’s their attempt at some kind of “fix.”

[ATSF_Ron]

Well, the saga continues.  I got some very small gauge wire from SBS yesterday and replaced the old ugly spliced wire with this one.  Problem is I'm back to square one with the shorting.  Very frustrating!  I'm almost 100% sure it's not my solder joints.  I was also super quick soldering the motor wire back on, however I may have damaged the dang brush cap or spring that Max and Peteski warned me about.  I found a longer screwdriver and tried the brush cap again.  I was able to tighten it from its original placement about one fourth of a turn.  After tightening, I can slightly lift the loco off the rails and it runs happy as a clam.  Put it in reverse and it's fine.  Forward?  Not so much.  Very odd.  In another interesting twist, I thought I had set the loco down with all drivers on the rails.  Unknown to me, the traction tire drivers weren't quite on the rails, but the dang thing ran JUST FINE forward!  Go figure.

Max, Peteski?  What am I looking for when I open up the brush cap?  I'm a bit hesitant to open things up and have the spring or other small parts go into the abyss, lol!  It wouldn't be the first time.

[peteski]

You're glutton for punishment Ron!   

I assume you are worried about the top brush hilder (the one with the wire soldered to it.  Well, from what I can tell in the photos. I don't see anything wrong with it. I would leave it alone Just make sure that the brass tab ti which the wire is soldered doesn't touch the motor's metal case.

The behavior you are describing sounds really weird. How can the model be running happy as a clam when the entire loco is lifted off the track?!  It needs to be on the track to get power from one of the rails.

Remember, the tender and loco are all metal and at opposite polarity from each other.  Since you are no longer using the drawbar to pass the power to the top motor terminal,  unhook the drawbar from the tender and make sure it is out of the way not touching any part of the tender (jut twist it to the side, out of the way). The only connection between the tender will now be the black wire.  Now try running the loco forward and backward, making sure the tender does not come in contact with the loco.  How does it behave?

[randgust]

OK, I'll take a haphazard guess.

Do the tender trucks only pick up from one side?  Most brass is that way, relying on the locomotive for the other.

If you've got a tender truck turned around, bingo, dead short.

[ATSF_Ron]

Randy, that was actually the first thing I found when I bought this loco a little over a year ago.  The rear truck was flipped!  I double checked and the trucks are fine.  Thanks for the idea, though.

Peteski, I am definitely a glutton for punishment!   So I tried your suggestion and bingo!  No more shorting.  WTH??  It wasn't doing this before I replaced the ugly wire with the new thinner wire.  You can even see in one of the pics the "washer" that the drawbar screws to is no longer connected to the motor wire.  As soon as I reconnect that drawbar there's a short.  I don't get what's going on here.  I understand one side is positive and the other is negative.  But how/why is there a short when I connect the drawbar?  The current setup is 100% identical as before the wire replacement.  I guess I'm an "electrically challenged" person, lol!

Also, as near as my eyes can tell with the optivisor, I see no contact to the motor from the brush holder.  I'm stumped!

[ATSF_Ron]

I almost forgot this...I took some needle nose pliers and gently bent the drawbar into a more horizontal angle, rather than the upward slant it had before.  Could that be part of my shorting problem?  The drawbar still looks 100% normal to me.

[peteski]

What this indicates to me is that the drawbar pivot post/spring/solder terminal on the bottom of the cab on the loco is somehow shorting to the metal loco frame. The drawbar, spring, and the post should be electrically isolated from the metal frame. I think it is just a coincidence that it happened when you replaced the wire.

Take an ohmmeter and see if the drawbar is shorting to the loco's frame.

Isn't remote troubleshooting fun?  That's how I make my living. 

[peteski]

I almost forgot this...I took some needle nose pliers and gently bent the drawbar into a more horizontal angle, rather than the upward slant it had before.  Could that be part of my shorting problem?  The drawbar still looks 100% normal to me.

Ah, so you did muck around with the drawbar!!!   

[Mike C]

  At this point I would probably just make a new drawbar from plastic . I've had a similar problem on an HOn3 model .     Mike

[ATSF_Ron]

Yeah, "mucking it up" is the polite way of saying what I really must've done, lol!

So, "Electronics for Dummies."  What setting should I use on my meter?  I just had it on DCV 20 to make sure I knew how many volts I was testing at, which was around 7V.  I would put one of the probes on the drawbar and one of the loco frame, yes?  Should I be running power to the loco?  I know, dumb question, but consider the source.

I can place the probes on each rail of track without the loco and get 7.4V.  When I place the loco on the track it shows 1.3V, which would indicate a short, correct?

[ATSF_Ron]

Mike C., I fashioned one from styrene that's the same size as the metal one.  I need to ream out the holes some more, as it's too tight of a fit.  I may just go back to the styrene drawbar.



Something is DEFINITELY up with that drawbar.  I'm trying to get a reading from the drawbar to the loco frame.  Each time I touch the drawbar the loco moves!

[peteski]

Yeah, "mucking it up" is the polite way of saying what I really must've done, lol!

So, "Electronics for Dummies."  What setting should I use on my meter?  I just had it on DCV 20 to make sure I knew how many volts I was testing at, which was around 7V.  I would put one of the probes on the drawbar and one of the loco frame, yes?  Should I be running power to the loco?  I know, dumb question, but consider the source.

I can place the probes on each rail of track without the loco and get 7.4V.  When I place the loco on the track it shows 1.3V, which would indicate a short, correct?

Oh man Ron, you are really glutton for punishment.   It would be prudent to at least know some basic electrical stuff before jumping head first into repairing tiny brass model locos.   

Most multimeters have an OHM and CONTINUITY ranges.  Put it on OHM and if you can select the range, select the lowest (usually 200).  The loco should not be on the track and the tender should just be dangling by the wire.

Next, take one of the probes and touch it to the drawbar, and take the other probe and touch it to any exposed metal part of the frame.  You can even touch it to the motor's frame since it is connected to the loco's frame.  Make sure that the probe is in solid contact with the metal part.

The meter will likely show a reading close to zero.  I guess you can also do this test using the CONTINUITY range of the meter. In that case, the meter will beep indicating a continuity (short).

If the drawbar is shorting to the metal frame of the loco then that confirms what we pretty much already know.  Replacing the drawbar with a plastic one woudl solve the problem, but that means you have to take the pivot point apart, and I remember how much you really "like" doing that.