Posted by: bgtwindad | December 10, 2012

Kato Genesis P42 Diesel Decoder Install

Kato P42

Amtrak #188 crosses the road, leading the Cardinal.

It’s been a while since I posted a decoder install how-to, so it’s about time I did so.  A few weeks ago, as a reward for some good news at work, I splurged on one of the Kato P42 Genesis Amtrak train “starter sets”.  The P42 Genesis is a really, really nice locomotive, one of Kato’s best in N scale, by many accounts.  It comes in the set as a DC model, but is very DCC friendly.  Digitrax, NCE, TCS and MRC all have drop-in decoders for the model (the MRC decoder includes sound!), and the install for all of them is quite similar.  In this how-to, we will be installing the Digitrax DN163K0A decoder, but you should be able to adapt this process easily to any of the other brands.

Here’s the locomotive in its packaging along with the rest of the train set (and my daughter’s “pet cow” Bessie).

The starter set

Step 1: Shell Removal

Shell Removed!

To remove the shell, pry the sides apart gently and insert some toothpicks to hold them out.  Pull down on the front trucks (gently but firmly – the trucks will pop out) and lift the shell off in a front-to-back motion.

Step 2: Unclip the motor tabs

Remove the grey clip

Near the center of the frame is a grey plastic clip holding two metal tabs (the motor contact tabs) down.  Gently pry up the clip and set it aside.  You’ll need it again later.  Then bend the two metal tabs up to free the light board.  You might want to take a sharpie and mark the spot where these metal tabs (used to) touch the copper pick-up strips that run under the light board.

Lift the motor tabs clear of the light board

(sorry about the focus on that one!)

Step 3: Insulate the pickup strips

Insulate the contact strips from the motor tabs

I’m sure there’s a more technical term for these, but those two long copper strips that run along the sides of the frame under the light board pick up power from the trucks and deliver it to the light board.  Remove the light board, and then gently lift these two strips out.  With a small piece of Kapton tape, insulate the spot where the motor tabs would touch these strips.  Be sure to insulate all the way around the strip, but don’t use more than one layer of tape.  The fit is fairly tight, and extra tape will make it hard to close things up.  Don’t use regular black electrical tape. it’s too thick, and doesn’t hold up well when heated.  Kapton is the way to go here.

Here’s what the insulated strips should look like when re-installed.

Replace the contact strips. Make sure they’re insulated from the motor tabs.

Step 4: Install the decoder

Install the decoder over the contact strips.

The decoder just drops into place where the light board used to be.  You’ll have to be careful not to dislodge the pick-up strips.

Step 5: Re-clip the motor tabs

Replace the grey clip. Press hard. Some extra tape might help.

Bend the motor tabs down so they contact the pads on the decoder.  Make sure they do not contact the pick-up strips!  Replace the grey plastic clip to hold the strips in place.  You have to press pretty hard to get the clip to snap in firmly.  If the clip is broken, or if you want to be extra-sure, you can solder the tabs to the decoder.  An extra strip of tape over the clip is also good insurance.

Step 6: Bend down the headlight

Bend the front LED down at an angle.

The last thing to do before re-installing the shell is to bend the front LED to about a 30-45˚ angle.  This helps make sure the LED fits into the light guide in the shell.   Once that’s done, slip the shell back in place, install the extra parts provided by Kato, and enjoy your locomotive!

Here’s a “wide shot” of the completed install:

And, of course, some video!


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s


%d bloggers like this: