KATO p42 install

[Rocsec1]

So I installed a new decoder in my P42. I can program it but it won’t run. Any ideas?
Thank you

[peteski]

Hi Rocsec, welcome to the Railwire.

It would be helpful to know what brand and model decoder, and what DCC system you use (to run and program the decoder).  The more details you provide, the easier it will be to troubleshoot.

For a quick basic check (for non-sound decoders) is to take a fresh 9V battery and touch it to the locos wheels to see it it will run.  Decoders usually have the analog mode turned by default in CV29, so DC 9V should get the loco running. Of course if you reprogrammed CV29 and disabled the DC mode, then you would have to change it back.  This exercise verifies the connections to the wheels and to the motor.

[Lackawannae8]

So I installed a new decoder in my P42. I can program it but it won’t run. Any ideas?
Thank you

did you isolate the pickup strips with kapton tape leaving the cut edge  toward the motor?
is the decoder slipped into the lock tab on the motor bracket?
did you solder the motor tabs to the board or use the grey clip?

[Rocsec1]

It is a digitirax DN163K0a Decoder and a digitrax Zyprers DCS50 Controller
I used the tape following the instructions, but what do you mean by the cut edge.the decoder is in the tab. I used the gray KATO tab with Kapton tape across it to hold it all in place. The tab wasn’t really doing the job.
I tried the 9v battery and the head light came on but no motor movement.power is coming to the decoder.

[peteski]

It is a digitirax DN163K0a Decoder and a digitrax Zyprers DCS50 Controller
I used the tape following the instructions, but what do you mean by the cut edge.the decoder is in the tab. I used the gray KATO tab with Kapton tape across it to hold it all in place. The tab wasn’t really doing the job.
I tried the 9v battery and the head light came on but no motor movement.power is coming to the decoder.

Then either the motor contact strips aren't making contact with the pads on the decoder (most likely problem), or the decoder is defective.  I really don't care for how the motor connection is handled on the Kato models of this design.

What's strange is that you were able to program the decoder. Usually when the motor is not connected the decoder will not present enough of a load on the programming track to be recognized.   But maybe your DCC system is able  to program the decoder "blind".

[John]

1)  Did the locomotive run before you put in a decoder with the stock light board?  - If yes, proceed to #2 .. if no - verify the motor is good. Try to use a 9V battery to get the motor spinning with the light board in

2) Tell us what DCC system you are using!!!!  It will help with giving you advice

[peteski]

Some answers are in reply #2 (and almost identical questions in reply #1) 

[John]

Some answers are in reply #2 (and almost identical questions in reply #1) 

I broke rule #1  -- RTFM

[Rocsec1]

It ran before
Digitrax zypher dcs50

[Rocsec1]

 Don’t like the  Design either. I just I did an sd70. Three pieces of tape, slide it on and you are done.

[POVC]

I had a similar experience recently, unfortunately I don't have a solution.

Brand new Kato P42 and brand new Digitrax DN163K0a decoder
P42 ran fine with a 9V battery
Installed the decoder, including Kapton tape on the pick-up strip IAW the directions, using the grey clip to hold down the motor tabs
Programmed the locomotive using a Digitrax Zephyr DCS-50; system read the decoder without issue and was able to program and read back addresses
Put the locomotive on the main and entered the address, lights worked with directional control, but no movement
Assumed the issue was poor contact between the motor tabs and the board, removed, cleaned the tabs, and reinstalled with no luck, although I could occasionally. get the locomotive to move by pressing really hard on the grey tab.
Finally decided to break out the soldering iron and solder the tabs down.
Put the locomotive back on the main, I had light control but still no movement.
Put back on programming track and attempted a factory reset on the decoder, but now all I get is a DNR error (although I still have directional control of the lights under the address I programmed).
At this point I gave up since I think I may have fried the decoder (at least partially).

Note that I too hate the way the decoder fits into the P42/E-8 mechanism.  I have 5 E-8's that I installed this same decoder in, and 4 of them have an issue with the board "losing contact" with the pick-up strips during operation.  The only fix I have found is to take off the shell and push down on a certain spot on the decoder, at which point it will start running again.  Due to the poor motor tab connections with the decoder, I had to solder the tabs on all of these, so "fixing" this issue is more complicated than a straight install and I haven't taken the time to go back and attempt a fix yet.

Tim

[peteski]

I didn't solder the motor contacts in my P42.  Instead I bent them as shown here. The gray Kato clip seems to put enough pressure on those bent contacts to allow the model to run.

I have not done a write-up for this install (I did it years ago), but the photos are all accessible in this album:
https://www.therailwire.net/forum/index.php?action=gallery;su=user;u=2700;cat=922

Some photos show alternate routing of the motor strips through the motor cradle - that is for another brand decoder which has motor power pads on the top and bottom of the decoder. Not applicable with Digitrax decoder.

I dislike depending on Kapton tape insulating the truck pickup strips from the motor strips.  Kapton tape also adds thickness to those truck pickup strips making the connection of them with the decoder less positive. As you see in the photos, I notch the truck pickup strips so they will not touch the motor contacts after the decoder is installed.

[GGNInNScale]

I replied elsewhere to a similar problem, I think.  I ended up soldering the motor leads to the board.  In spite of the bumps on the bronze strips, etc, etc. I could not get the gray plug to hold.  I used the tape as noted.  Now, I hard wire or solder all motor connections.

[Rocsec1]

Ok so now I gotten the cli0 to hold and the as soon as I turn on power to the track the loco goes no matter what the power setting is.
Drop in my butt.

[peteski]

Ok so now I gotten the cli0 to hold and the as soon as I turn on power to the track the loco goes no matter what the power setting is.
Drop in my butt.

You mentioned earlier that you were able to program the decoder, but can you actually read any CVs (on the programming track).
Also as you are reading the CVs, can you see the loco move or jerk slightly?