Diagnosing a Kato sprung frame....again

[primavw]

This type of post for me is starting to become a trend. It seems like half of my Kato sprung frame locos are either working poorly, or not working. Last night while running one of my fave locos, an N scale Kato Mid-pro SD40-2 (unknown DCC decoder installed), I noticed it was becoming more and more jumpy (start stops). I flipped it over and found there was some fibrous junk clogging the gears of the trucks. So, I dropped the trucks out of both sides and gave the gears a good cleaning. I replaced them and laid the loco on the track and NOW IT HAS NO PICKUP. I pulled the trucks and set the frame on the rails and got the LED's to respond (although the motor won't turn when I throttle up). I tried to place just the strips on the rails and it has no pickup. How can this even be possible?

I know there has been rants about these things in the past, but I am really starting to LOATHE anything sprung that Kato has put out. Even some of my ACE's run like complete crap. So... what the heck is the problem????

[victor miranda]

Hi primavw
 a guess.
I am thinking you have fuzz in the pickup cups.
This is because you have fuzz and did not mention removing the axles.

victor

[GaryHinshaw]

I'm no fan of these mechanisms either, but your problems don't sound like they are specifically due to the sprung design.  I'm especially puzzled by the fact that the LEDs will respond but the motor won't when you have the frame on the rails. 

I tried to place just the strips on the rails and it has no pickup. How can this even be possible?

I don't understand this statement.  Do you mean you had the contact strips attached to the frame, and you placed the other ends directly on the rails?  If so, then you are saying that the contact strips are not making proper contact with the frame, correct?  It might help to post some photos of the offending loco.

[peteski]

I'm also a bit confused by the problem description.  While I don't have much experience with that mechanism (I have a GG1 but I haven't tinkered with it yet), friend of mine has several of that style locos and they run like Swiss watches.

I once troubleshoot couple of misbehaving trucks - see page 2 of the old A-board thread http://forum.atlasrr.com/forum/topic.asp?TOPIC_ID=65549 BUt you seem to have a different problem (more related to the frame contacts).

[Bob Horn]

I have around 15 of them, none of the GE, all ACes, and SD-40-2's. Really no problem with any of them. 3 SD-40-2's I installed Digitrax sound in. It can be a finicky drive but really performs very well. I have had truck bottom plates come off in a hard pull but when reassembled it did not happen again. On top of mine I have installed decoders in about 20 others. Bob

[primavw]

Sorry, yes I meant the copper contact strips that provide pickup from the trucks to the frame. I attempted to place the contact strips, while still attached to the frame (no trucks) directly on the top of the rails and can't even get the LED to respond...

[primavw]

Well, I'm still wrestling with this little issue... and I discovered this:




I'm guessing due to the extra strain on the gears caused by the fibers in the teeth, it caused the trucks to warp? Anyone been through this? I'm tearing down the trucks to see if I can get the wheelsets re-seated... I'm not sure if this is the answer to the conductivity issue, but I guess it needs to be addressed anyway?

[Bob Horn]

Long ago offer still stands. The truck is not assembled correctly, not due to fuzz, just not right. Bob.

[JanesCustomTrain]

From what I can see on these dark pictures, the truck did not warp but it looks who ever put the truck back together did something wrong. on one side the brass pick up is installed correctly on the other side the brass pick up is somehow bent under that support guide on the gear tower. Take it apart, bend the brass pick up into the right shape and put it back together and it should run fine.

The truck has to look like this on both sides (see the brass power pick up) http://www.katousa.com/images/929341.jpg

Jane

[primavw]

Update: Up until a week ago, I probably wouldn't have attempted tearing down the trucks, but due to a side project I have going on which required me to paint BNSF Green trucks back to black, I was somewhat comfortable cleaning these.

Hopefully you can see this:


I'd say 4 out of 6 trucks had these little lint wads on the ends of the wheel where it meets the copper piece. I cleaned the trucks thoroughly over the last 45 mins or so and got the trucks trued up again. I also gave them a good lubing and cleaned out the brass strip channels on the frame.

Unfortunately, this did NOT solve the issue. I placed the loco on the programming track and it is not reading the decoder. I'm not sure if this is an unrelated chain of events, a problem caused due the loco working harder because of the gummed up drivetrain which then caused the decoder to fry, or if the decoder STILL isn't getting power from the rails, but I'm not sure what to do next. I did shim the decoder which did nothing. I guess I can try dropping in a spare DC board to see if that will move the loco... sheesh

[JanesCustomTrain]

I guess I can try dropping in a spare DC board to see if that will move the loco... sheesh

Yes do that first, establish it runs fine in DC and then go further... sheesh

Jane

[victor miranda]

good to know fuzz gets everywhere... and my original guess had some merit.
Be aware that fuzz can get into worms and motor shafts.

from the photo of the truck, I can see it is mis-assembled.
that alone will cause the problems you have.

there are a lot of ways to test. alligator clips and wires  are good to test motors
and DCC boards.
get the motor going on DC if and only if you can disconnect the DCC decoder.

victor

 

[nightmare0331]

Well, I'm still wrestling with this little issue... and I discovered this:




I'm guessing due to the extra strain on the gears caused by the fibers in the teeth, it caused the trucks to warp? Anyone been through this? I'm tearing down the trucks to see if I can get the wheelsets re-seated... I'm not sure if this is the answer to the conductivity issue, but I guess it needs to be addressed anyway?

one pickup is caught under the worm gear cover.  (1st photo on the right, second photo on the left).

http://www.katousa.com/N/SD40-2/maint/disassembly.html

step 3b, read the note on the brass nubs that come up from each side. 

Use a toothpick or a set of tweezers to carefully nudge the contact from under the worm cover clip and up.  This should mostly rebalance the truck.

Hope this helps!

Kelley.
www.dufordmodelworks.com

[victor miranda]

nightmare0331,

I like your reply.  I've none of these units and
I had no good advice to give for how to fix the issue with the trucks.

I hoped that more than one person saying the truck is not right
would nudge him look for the solution to assemble it as Kato designed.

victor

[primavw]

As I noted in a previous post, I reassembled the trucks and they are true now. The "fuzz" was causing the wheels to push out of the brass stirrups. I have since dropped in a DC board and the loco is running fine. I guess I need to see if Digitrax will honor the warranty for the DCC board.