Sunday, October 16, 2011

TCS M1 in an Atlas SD50

The engine that I happen to be using in this post is an SD50 but the mechanism is the same for the SD60 and SD60M.  Besides the TCS M1 decoder used here, any similar sized decoder would also work.

Today's small DCC decoders as well as the design of this popular model make it possible to easily install a wired decoder a less expensive alternate to the board type decoders that are made for these models.  No frame modifications are needed.

After dis-assembling the loco mechanism, make the modifications shown in this photo.  The hole is on the long hood end of the PC board which has the longer wide area.  Wire thickness may be different for each manufacturer of decoder so size hole for the decoder you are using.

Bright white LED's were added on later releases of these models and the PC boards were re-designed.  There is an extra part on these boards labeled C1 that will not be needed in a DCC engine and this should be removed.  If you have one of the older versions with the yellow LED's and want to replace them with bright white LED's now is the time to do it.

Guide all of the decoders wires through the hole from the bottom of the board.  Attach the decoder to the bottom of the board with Walthers Goo.

Stretch out each decoder to the point that they will be attached to on the board and cut them about 1/4 inch beyond that.  The gray and orange wires will be attached to the motor and I use the line shown on the photo as a length guide for them.  This gives a little slack in the wires to work with.
In this photo the red, black, white, and yellow wires have been soldered to the board.  The scrap piece of the blue wire gets used to connect the front LED.
Study this photo closely.

Trim the motor brush tabs to be even with the top of the motor.  Guide the orange wire around the right side of the board and the gray wire around the left side and through the motor saddle.

Place a 1/4" length of 3/64" heat shrink tubing over the end of each wire.  Solder the orange wire to the right motor brush tab and the gray wire to the left motor brush tap.  Carefully heat the heat shrink tubing then place the motor saddle over the motor from the left side.  To make this operation easier is why the length of the orange and gray wires were left as long as they are.

Install the motor, board, and worm gears into the right frame.  The fit for the board should be snug to have good contact with the frame.  Then re-assemble the left frame, trucks, and fuel tank, then it's ready for a test run.  The left frame should also be a snug fit with the board.
The original paint on many of these models won't block of light of the bright white LED's and it will glow through.  I often paint the inside of the shell around ends with Floquil Old Silver.  It also helps to use the same paint around the LED's leaving just the end clear for light to shine through.

Monday, October 10, 2011

TCS Z2 in a Life Like SW9/1200

The Life Like SW9/1200 has always been one of the more challenging N Scale locomotive to get a decoder into.  No decoder has ever been made specifically for this model so it's been up to the modeler to fit in a wired decoder.  I've done a number of these engines and over the years I updated my technique.  What is shown below is the most reliable method that I have found.

Start by removing the fuel tank.  Then each of the trucks can be removed by turning them as shown.  Be careful not to bend the contacts that are attached to the body.

Next, remove the cab shell after unplugging the center hand rails from the cab.  The heavy steel weight may come off as well and that is OK.

Some may feel that inside the cab would be the obvious place to put a decoder.  I don't agree with that approach because this is where most of the weight is in this small engine.   I have tested these with just the heavy steel weight removed and found that the engine lost much of it's traction and pulling power.

It is important to remove the shell without damaging those contacts that are attached to it.  I made up a set of shims from .005 brass sheet.  These are slipped between the frame and the body to prevent the contacts from catching on the frame.

Slip the shims carefully between the frame and the contacts where the contacts go between the frame and the body.

Once the shims are in place, the frame can be separated from the body by pressing the exposed part of the frame down as shown in this photo.

Once the shell and the frame have been separated, disassemble the frame to the point shown here.

Remove the LED and the resistor from the little PC board.

Cut the Train Control Systems Z2 decoder's wires to the following lengths:
Gray = 1-1/2 inch
Orange = 1-1/8 inch
All others = 1/2 inch

Strip 1/16 inch from the ends and then tin the ends of the Red, Black, Orange, and Gray wires. Remove the LED and resistor from the circuit board. Solder the red and black wires of the decoder to the points on the circuit board shown in this photo.

Then the decoder is attached to the PC board with a drop of Wathers Goo.  It is positioned so that it is in the spot where the LED was.  In this photo an original LED board is shown next to the board with a decoder mounted on it for comparison.  The decoder is longer than the LED but is narrow enough to fit between the frame.

The Goo will need 12 to 24 hours to set and it's best to use a clamp of some sort to hold the position.
Once the Goo has set, the decoder / PC board should look like the one in the bottom of this photo.  Remove the motor from the plastic saddle and then remove the brush contact clips.  Cut them down to the shape shown in the photo and solder the gray and orange wires to them.  Remember the orientation of the motor, the hole is towards the top.

With a jewelers file cut a groove down the left side of the motor just large enough to fit the orange wire into.

Then clip the orange wire to the top brush holder, and the gray wire to the bottom brush holder.

Lay the gray wire in the groove and wrap Kapton tape around the bottom of the motor so that it is covering the bottom brush holder and ends at the top of the motor on each side, which holds the gray wire in the groove.

Install the motor back in it's plastic saddle and then the frame can be re-assembled.  Plug the LED board into it original spot.  With a toothpick place a small amount of Goo between the motor and the plastic motor saddle on each side of the motor.  Let it get tacky then press the motor wires into that spot.

The short white, yellow, and blue wires can be secured the same way as shown in the photo or they can be just cut off.  I like to keep any unused wires on a decoder available in case they can be used in the future.  As an example, I have re-used several decoders  that had burned out motor outputs as lighting function decoders.

Almost done:

Check that the flywheel turns freely.  Then test the mechanism by attaching alligator clips between a DCC source and each side of the frame.  If that test good, then re-install the shell, the shims are not needed to re-install it.  Install the trucks and fuel tank, then test again on the track.  If that test good then re-install the weight and the cab and re-install the hand rails. 

Thursday, October 6, 2011

Add terminal strips to DCC Specialities PSX-1

OK, so this is not exactly a decoder install.  But I found that I really like these solid state DCC circuit breakers and figured anyone who was into DCC in any scale might benefit from this information.

This is a great little unit for setting up power districts on a larger layout.  It's a solid state circuit breaker that will trip when there is a short on the track and then clear itself when the short is cleared.  The basic hookup is real easy and there are also options on the board for the following:
  • Track power on remote LED
  • Track shorted remote LED,
  • Block occupied input
  • Block occupied remote LED
In my application I was installing 6 of these into a portable DCC power unit for a modular layout, that might be another post sometime.

The board comes with the green terminal strips on the ends for the DCC in and out but nothing for the other external connections I wanted to use.  I did not want to just solder the wires to the holes and the instruction sheet only says "Available from your dealer".

The spacing between the holes on the board for J4, J5, J6, J7, & J11 I thought was somewhat uncommon at 3.5mm but I was able to find a perfect fit.  Because all of the holes are in even numbers and the functions connections in pairs, I decided to use a 2 position terminal strip.  This type of terminal strip can be mechanically linked together to form a larger terminal strip as needed. 

I wanted to use the optional connections for track power ON and track shorted remote LEDs but the terminal strips I found will work for any of the external connections related to any of the optional functions.

Source:  Digi-key Corp.
              701 Brooks Ave. South
              P.O. Box 677
              Thief River Falls, MN 56701-0677

Here is the information for the terminal strips.  It is actually cheaper to just get the 2 position ones and link them together as needed to make bigger terminal strips.

 Digi-Key Part #      Description                                                 Cost
281-1402-ND          Weidmuller 4-pos 3.5mm pitch terminal          1.89
281-1400-ND          Weidmuller 2-pos 3.5mm pitch terminal            .89

 Here is a link to the DCC Specialities instruction for the PSX-1: