Sunday, January 22, 2012

TCS Z2 in an older Atlas RS11

This is an old engine without the LED lights, flywheels, low friction trucks, or Micro-Trains ready coupler pockets that we have become accustomed to.  At about the time DCC started to catch on with N scalers in the early 1990's, this was a very common mechanism that was used on several models made for Atlas by Kato in the mid to late 1980's.   They do have a good motor, and with a DCC decoder momentum can be programmed to help make up for the lack of flywheels.

First step is to take the engine apart.  Getting the shell off is the hardest part.  Here's the trick.  First remove the cab to expose the catches that hold the shell to the frame.

Once the cab is off, the main part of the shell can be easily removed as shown in this photo.

This photo shows all of the parts after this RS11 has been dis-assembled.

This mechanism is almost identical for the Kato made Atlas RS3, RS11, RSD4/5, RSD12, GP7, and GP9.

Here are the lengths that I cut the decoder wires to.

2" - White
1-7/8" - Red & Black
1-3/4" - Orange
1-1/4" - Gray
7/8" - Yellow & Blue

This photo shows the decoder wires solder to the modified light boards and the motor brush caps.

The next two photos show the details of the light boards.

The PC boards are the same as the common Kato 77A board.  It's just that these have a light bulb and a diode instead of a LED and resistor.  The directional lighting will be determined by the decoder so the diodes are not needed.

The red and black wires from the decoder will make their connection to the frame from this board.

On the rear light board I cut off the tabs with a Dermal tool, removed the diode and soldered the blue and yellow wires from the decoder to the light.  Polarity will not matter with the light bulb.  A second blue wire was run between this board and the front board.

Re-install the brush caps with the brushes and springs on the motor.  Then place the motor assembly into the left side frame as shown in this photo.  This one did not have any separate worm gears or bushings, it was all attached to the motor.

Here is the completed DCC mechanism.  As you can see, there is lots of room for the decoder.  Any of the small wired N or Z scale decoders could fit in this space.

Finishing Touch

These older engines had truck mounted Rapido couplers with big openings on the pilots.

Micro-Trains made pilot conversion kits and these are still available.  For the RS11 look for Micro-Trains part number 1150.

Friday, January 6, 2012

TCS Z2 in a Life Like C-Liner

We start a new year of installing DCC decoders in N scale locomotives.  This year will be almost all new material as I think I've used almost all the old material I once had on the nscalestation web site. 

First up will be the Life Like C-Liner

I sent the frames to Aztec Mfg for milling.  This photo shows what is removed from the frame.  Because of the way the motor mounts into the frame with no plastic saddle, the space around the motor is tight and it's important to have the spaces milled around the motor so the brush caps don't touch and wires don't get pinched.

Just like I do with Kato F units, I take the extra step to drill and tap holes for size 2-56 screws that will be used to attach the decoder wires securely to the frame.  This would be a requirement on the B's anyway because there is no light board so I just do it for both A's and B's.

In this case I am using a TCS Z2 but any of the small decoders available today should fit in the space provided.

The wires are cut to the lengths indicated in this photo.  Then the brush cap are removed from the motor and the orange and gray wires soldered to those.  The motor brush contacts that are removed with the brush caps and then soldered to the red and black wires.  These will be secured by the screws to the frame to provide a reliable connection.

This step is done on A units only.  With a Dermal motor tool and a cutoff wheel, I remove the circuit traces that could connect the board to the frame.  Then I also make a notch in the front edge of the board that the blue and white wires pass through.  The blue and white wires are then soldered to the board as shown in this photo.  On this one I kept the light stock light bulb so a resistor is not needed.

After re-installing the motor brushes into the motor, the motor, gears, and bushings are all re-installed into the right side frame as shown in this photo.  Take care that the orange wire is in the channel and not being pinched between the motor and frame.  This model has a spacer with an odd shape that goes on the front.  Notice the orientation of the spacer.

Install the left side frame and install the nuts and screws.  Then use the 2-56 x 1/4" screws to secure the red wire to the right side frame and the black wire to the left side frame.

This is the completed mechanism for a C-Liner A.  Double stick tape is used to secure the decoder and wires. Test run the mechanism then if satisfied with the way it runs, install the shell. The shell on this model goes on straight down so that ribs inside the shell fit into slots on each side of the frame.