This is another one of those installations where I am using a standard wired decoder on a model that was designed to take a specific board type decoder. In this case the model is the Kato SD40 built on a mechanism that can use either the Digitrax DN163K1B or the Train Control Systems K1D4 board type decoders. Releases of the SD40 and SD45 after 2002 use this mechanism. It can be impossible to know what you have until the body is removed exposing the mechanism.
Here is a comparison of the two mechanisms.
The upper photo is the older version and requires the frame to be modified to get any decoder into to it.
The mechanism in the lower photo is the later version which accepts a board type decoder.
Sometimes it happens that someone gets the wrong decoder because they are mistaken about which version they have. While the board decoder can't be used on the older version there is no reason a wired decoder can't be installed in the newer version.
Looking again at the newer version of the mechanism and comparing a TCS M1 wired decoder along side it can be seen that there is space for this or other similar small decoder under the LED on the long hood end.
As with my other installations where wired decoders are connected to existing boards, the board receives some modifications. The first step is shown in this photo.
A small section of the circuit traces are removed in the seven locations shown in red in this photo to isolate the various functions.
Then the capacitor that is installed across the short hood end is removed. This was added by Kato after it was realized that when running at high speed on DC the trailing end bright white LEDs would flicker. Since this is not going to be an issue using the decoder it can be eliminated.
Next an additional resistor needs to be added at the location shown in this photo. The value on the resistor should be the same as the existing one. They will have either a number 271 (270 ohms) or 561 (560 ohms) on them. I got mine from other stock Kato boards I had but this type of surface mount resistor can be purchased from Electronics supply sources.
All of the decoder wire connection locations are also shown in this photo.
Just as with the board decoder installation, Kapton tape is placed across the top of the frame and over the sides to insulate the frame from the contact wings that extend down from the board.
I found it works best to install the board on the chassis first then put the decoder in it's place and cut the wires to length starting with the ones closest to the decoder.
This photo shows how I placed the decoder with the wires facing backward but it could go either way. The wires can either go between the leads of the LED or around to one side.
This photo shows all the wires connected
When re-installing the shell, it should rest upon the tabs that stick out from the frame as pointed out by the green arrow in this photo.
For quite a few years Life Like had offered N scale models of the EMD SW8, SW9, and SW1200 switch engines in many road names. These were never decoder friendly, and have always been one of the more challenging models to do an installation on. In 2011 I posted in the blog about installing a TCS Z2 in a Life Like SW9/1200 and it's been the most popular post.
A few years ago the Life Like line was acquired by Walthers, and it appears that Walther's has discontinued production of this model. More recently Micro-Trains released a model of the SW1500 which is using a very similar mechanism to the one used on the Life Like models.
Shortly after Micro-Trains released the SW-1500 switcher model, Train Control Systems came out with a decoder for it called the model MT1500.
I wanted to see if this new decoder would also work on one of my Life Like SW8's that had not yet received a decoder.
The first challenge in this installation is to remove the body from the mechanism without damaging the contacts that are attached to the inside of the body.
To do this I made a set of 4 shims as shown in this photo. The shims are shown here with a ruler as a size comparison.
The shims are inserted between the frame and body at the points shown in this photo. Then the frame can be carefully removed from the body. It helps to first remove the cab section and weight, then the frame can be pushed out from above.
The MT1500 decoder does not come with any wires because the installation in the Micro-Trains SW1500 uses the wires that are already in the locomotive. Scraps of wire left over from other wired decoders were soldered to the motor contact clips after they were cut down to the sizes shown in this photo.
After re-attaching the motor contact clips to the motor and installing the saddle the assembly should look like this. The orange wire is laying is a small groove that I had filed in plastic body of the motor.
After re-assembling the mechanism it should look like this photo. The wires from the motor will plug into the sockets on the decoder board. Lay the wires down flat as shown so they won't get pinched when the body in put on the mechanism.
The SW1500 decoder has a tiny LED headlight which operates as function F0 which is great. It also has the option of connecting another light or LED to some very tiny contacts on the decoder board.
If you are up to trying to solder wires to these then this could be programmed for a rotary beacon or mapped to function F0 in the reverse to add a headlight on the back of the cab.
After getting the body back on the mechanism it's good to check the coupler height on both ends to insure the body is on correctly. I had no problems with mine. This was the easiest installation on one of these models I've done. The MT1500 is a welcomed addition to the TCS line of decoders.
Yes, this is yet another type of Atlas GP7 installation. This installation follows an older technique that I don't use much anymore but in this case the model already has a Richmond Controls lighting unit installed and the goal is to continue to use it being controlled by the DCC decoder.
Richmond Controls of Richmond, Texas has been providing small lighting modules for model railroaders for many years. Features may include constant brightness head lights, MARS lights, simulated rotary beacon, and other similar features. For more information about Richmond Controls check out their web site.
This photo shows the Richmond light module on the left at the short hood end of the frame. It's input is wired to the standard LED board on the long hood end to get contact to the frame.
First I wanted to verify for myself that the Richmond light module current draw was within what the function output of the TCS M1 decoder could provide. The current draw was between 5.5 and 6.1 ma depending on the cycle of the rotary beacon. This is well within the stated 100ma rating for the M1's function outputs.
A variable DC power supply was used for this test and the current draw did not change much between 6 and 12 volts.
To start this installation, the mechanism will need to be fully disassembled.
Normally on a straight forward DCC install on this model, I would have used a TCS CN-GP decoder without frame modification.
In this case to have room for the Richmond module I went back to my old method of using the TCS M1 wired decoder and a frame milled by Aztec Manufacturing.
This particular model is notorious for being noisy. This has been traced to vibration of the inner bushing of the worm gear assemblies. The assembly will support itself between the outer bushing and the flywheel so the inner bushing can be removed. While this is apart for decoder installation is a good time to do this.
I did not invent this technique myself, but read about it years ago in N Scale magazine. Here is a PDF reprintof that article.
To remove the inner bushing, first pull off the hex shaped part from the end of the shaft then remove the bushing and put the hex part back on. The hex part must be a tight fit on the shaft as it is what interfaces with the flywheel. I will normally use adhesive such as E6000 to secure this part to the shaft.
Tip:
If you ever have a locomotive where one or both sets of wheels don't turn when the motor is running, check this or it's equivalent part for being loose on the shaft.
The decoder wires are cut to the following lengths:
Black / Red = 2 inch
Orange = 1-1/8 inch
Gray = 1-5/8 inch
The White and Blue wires can be left alone for now.
As with many of my other installs, I file a groove on the side of the motor body for the longer of the motor wires to reach the bottom of the motor
One of the original LED boards is cut off so that there is just enough circuit trace sticking out from the frame to solder the red and black decoder wires to. This is then installed at the short hood end of the mechanism.
The Richmond Controls module is then attached to the frame in remaining space with either double stick or adhesive.
The yellow is cut to a length that will allow it to be folded over the decoder and connected to the cathode side of the T3 size LED.
The blue wire from the decoder is cut a bit shorter than the yellow wire and then spliced with the section of blue wire that was cut off. Both are then connected to a 680 ohm 1/8 watt resistor. The resistor is then connected to the anode side of the LED. Heat shrink tubing is used to cover these connections.
The remaining blue and white wires from the decoder and the red and black wires from the Richmond module can now be cut to a length that they will meet and can be spliced. A 1000 ohm resistor was placed in series to hopefully prevent any over voltage to the Richmond module. Splices are contained within small heat shrink tubing.
When the body is placed back on the mechanism, care must be taken with small wires to the rotary beacon.
Also, it is best to check the coupler height for both ends of the locomotive against a Micro-Train reference. This the body of this model is a loose fit on the frame and if the body is sitting too low it can cause coupler height problems and the bottom of the body hitting the rails. It may be necessary to place shims made from polystyrene strips on the inside of the top of the body.
Recently I've been learning how to work with YouTube a little bit and thought a good way to end this post was with a short video showing the simulated rotary beacon on this model in action.
I recently did an install on one of the more recent releases of an Atlas GP38-2 using the TCS M1 decoder. While this install is similar to other installs I have presented using a wired decoder instead of a board decoder I discovered some differences that made it worth it's own post.
After dis-assembling the mechanism I discovered that the motor had a different type of brush holder than those found in most Atlas models. This model uses the Kato style of brush holder with a separate cap.
The plastic motor saddle had also changed. Because the brush holder with cap sits flatter than the one piece type, the saddle had a block on both top and bottom. I found it necessary to remove the top block with a file to get a good fit.
The board requires the same type of preparation as the board did on the Atlas Master Line GP7 that I did about a year ago.
For more for details on how prepare and wire the decoder to the board check HERE.
This model comes with the little spring clips on the original LED board. I've never had much luck with these and the ones on the board fell off so I used the solder method to thicken the board for a good fit into the frame.
After re-assembly the mechanism looks like this photo. The model I did was actually a GP38-2 but a master line GP38 should be an identical mechanism. I test ran this model with an earlier release GP38 and the speed of this new motor seem to match the older release perfectly.
About a year ago I presented an installation where I used a TCS M1 decoder on an Atlas Master Line GP7 which is intended to take a board type decoder but does have room for wired decoder using the existing PC board. To see that post clickHERE. Recently I was asked to install TCS ASD4 board type decoders in several similar models so I thought it would be good to present that type of installation as well so someone could make the comparison.
What happens sometimes with these decoder board type of installations is that the contact tabs from the motor don't line up with the slots on the board. The photo shows how I check for this, lining up the frame to board contacts first then checking alignment of motor contacts.
It's not hard to fix this problem by hard wiring the motor contact to the board. I use scraps of orange and gray wire left from wired decoder installations. It does not matter which color wire is used as long as the wire from the bottom brush goes to the forward slot and the wire from the upper brush goes to the rear slot just as the tabs would if they lined up properly.
Cut the tab from the lower brush short and solder a wire to it, then slide a short length of 3/32" heat shrink tubing over it.
For the top motor brush first remove the brush holder and take the tab off. Then solder the other wire to it. When cooled re-install holder with spring and brush into motor body.
After both wires are attached to the motor assembly, slip them through the plastic motor saddle as the saddle is pressed onto the motor. When that's all done the finished assembly should look like this photo.
Another issue with the board type decoders is that they sometimes fit loosely in the frame. On this one I fixed they by adding a small amount of solder to the contacts on the bottom side of the board. On this model I found that a thickness of .030 was about right to get a snug fit.
Press the board into the right half of the frame, it should fit snugly. On these Master Line GP7 and 9 models, there may be a small plastic button. That goes into the right side frame as shown here.
When everything is all put back together it should look like this. The wires need to lay in between the frames.
A nice thing about this decoder board is that is has big solder pads to easily connect extra lighting functions.
In some future post I will show some ways to use these additional functions.
At a recent train show one of my buddies from the Ntrak club I belong to asked me to take a look one of his Kato SD80Mac locomotives. His complaint was that while it did run, it was slower than other identical locomotives. I verified this on my test layout and it seemed to get worse the more I ran the locomotive. I then took the shell off to test the motor for current flow and this is what I found.
Apologies for this blurry photo.
The kapton tape was coming into contact with a rotating part of the motor as indicated by the arrow on both sides preventing the motor from turning freely. This put an overload on the decoders motor output.
This photo shows how the installation should look. The kapton tape comes over the side of the frame on each side and stops before reaching the open part of the motor.
This type of installation is common to several Kato models. They are generally an easy DCC installation but it is a good practice to always check for free rotation of the motor when doing an install.
When I put the decoder on my test fixture, the voltage on the motor output of the decoder was zero when connected to the test motor but was normal with no load. There was no sign of anything burned on the decoder. A reset was programmed into the decoder but this did not clear the problem. In this case the decoder needed to be replaced.
Before installing the replacement decoder the current draw of the motor was measured by connecting the motor directly to my bench DC power supply as shown in this photo. It is rare but I did once see a defective motor cause a decoder to burn out and that became thefirst post on this blog.
Not much new decoder installation material to report on lately but recently at a local show one of the guys in the Ntrak club was having trouble programming one of his Kato E8A's that he had just put a decoder in. On our Digitrax system the throttle display indicated "NoPrG".
This photo shows the decoder installation. A visual inspection indicated that everything was done according to instructions.
What I found when I got this loco to my bench was that the motor contact strips were not making good contact with the board. This is a common problem and I always solder the contact strips to the board. What happens is that a current has to pass through the motor to complete programming. That is why you may notice a loco move or feel a vibration when sending it a program. On this type of mechanism the motor brush contact strips are held in place against the board by a plastic clip. This clip by itself sometimes does not stay tightly in place.
This closeup shows how the motor contact strips are held against the board by the clips. To solder the contacts in place, remove the clip and melt a small amount of solder to both the board and the bottom side of the contact at the end. Then use a small screwdriver to hold the contact tight against the board while re-melting the solder making the bond. Care needs to be taken to avoid melting the kapton tape on the wheel pickup strips.
If soldering is not an option then I would suggest a thin piece of scotch tape be placed over the plastic clip and reaching the gray plastic motor saddle on both sides to help keep the clip from coming loose.
It is even possible that a loco could seem to run OK in DC or DCC and then show this same programming problem. That is because the contact is not good enough to pass enough current to make the programming function work but enough current could flow to turn the motor. I've also seen this happen a time or two on a wired decoder where the connection to one of the motor brush caps was just hanging by a few strands of the wire.
On this Kato E8 it is interesting to note that this particular mechanism was introduced by Kato in 1994 and was one of the first mechanisms designed to accept a board type decoder even though it would be a few years before such a decoder was available. Since then several other models have be been introduced that use this same design on similar mechanisms.
