TCS Z2 in an Atlas H16-44

The Atlas H16-44 is an unusual model because it has green and red marker lights on each end in addition to a LED head light.  The green markers come on at the leading end of the engine along with the headlight.  The red marker lights are lighted come on at the trailing end.

At the time they were available for sale they came in a DC or DCC version. None of the decoder manufacturers ever came up with an after market decoder for this one so if you want to add DCC to one it's going to be a wired decoder.  I chose the small and reliable TCS Z2 with functions rated at 60ma driving 3 LED's should be no problem.

After some experimenting, I determined that to get the red and green LED's to light using a DCC decoder, both of the 3 lead LED's on the stock board are going to need to be replaced.  This is because they are a common cathode type which means the center or common lead is connected to the negative side of a power source.   On a decoder's function outputs, using the blue wire as a return, it's the blue wire that is positive relative to the white and yellow wires.  Because the LED cathodes are tied together on the PC board, the headlight LED's will also need to be reversed.


I drew up this schematic to show these connections.

I got my 3mm common anode, 2 color ( red / green ) LED's on line from LED-Switch,  www.led-switch.com.  Their item number was L033RGDCA.  It was only $1.50 for a bag of 10 plus shipping.  They are worth checking out anyway as they have quite a few good items for model railroaders.

I could not determine any difference between the common anode and common cathode types of this LED from looking at it.  The only way seems to be to test it.

The method I use is shown in this photo.  If it lights with the + side of the 9 volt battery connected to the center, then it's common anode.  Don't forget the resistor !


There will also need to be some minor modification to the frame so start by fully disassembling the locomotive, placing all the small parts in a plastic bag.    Always put the motor assembly in a separate small plastic bag so no small metal objects will get into it because they are attracted by the motors magnets.  But before putting the motor away see the step below.

There is little plastic part that fits over the end of the motor shaft inside both flywheels.  I found several of these to be quite loose.  This is intended to engage with the worm gear shaft and if it's loose, the mechanical energy won't be properly transferred to the worm gear.

Check both and use adhesive if needed.  I used the E6000 product that I have mentioned in other posts.

I will use the original light board but will cut a section out in the middle to make room for the decoder.  It will end up being two boards with one being longer than the other.

Three diodes and one capacitor will be removed.  The LED's with 3 leads will to be replaced with the common anode ones. The LED's with the heat shrink need to be swapped from one end to the other.

One circuit trace needs to be cut.

The modifications required on the original LED light board are all shown in this photo.

This photo shows  what is now two separate boards should look like after the modifications and where the decoder wires are going to connect when we get to that step.

When installing the new common anode LED's it is important to keep the flat edge of the LED facing the same way as the old one was.  On this type of LED, the flat edge indicates the side for red.

On the the frame modification, I have temporarily placed the PC boards into the frame to gauge the spacing.  The decoder will fit into the wide opening in the top of the frame but that opening needs to be made longer as shown in this photo.

After the material is removed from both frame sides they should look like this.  This is the most time consuming part of this installation but it is important to take the time to be careful working with the frame.

To get the decoder ready for this locomotive cut the red and black leads to 1/2 inch, cut all the others to 5/8 inch.  Strip about 1/16 inch from each of the decoder wires and from one end of the blue, white, and yellow scraps.  Then twist the scrap ends together with their matching color wire from the decoder.

This photo shows what the decoder should look like after this step is completed.  Tin the ends of all the wires, this will keep those twisted ends together.

The next step is to connect the motor to the decoder.  I used a combination of two techniques that I have used on other installs.  The orange wire gets soldered to the wrap around contact to the bottom motor brush and 3/64 inch heat shrink placed over it.  The gray wire gets soldered directly to the top motor brush cap. Remove the brush cap first to do the soldering and then re-install it afterwards.

Put the motor back in it's mounting saddle and re-assemble the mechanism. It should now look something like this photo. Check that both the orange and gray wires are not touching the frame. The heat shrink tubing should protect the contact strip and the orange wire from the frame.

Test fit the shorter PC board, it should fit tightly on both sides. If it is loose on either side, remove the board and tap lightly a few times on the top of the frame at the spots indicated by the blue arrows.  Re-check the fit of the board.  Go slowly and repeat as many times as needed until satisfied that the board is making solid contact with the frame.

Connect all of the wires according to the photo shown several steps back.  When connecting the double yellow wires, place a small length of 3/64" heat shrink over it as there are exposed points on the board very close.  Solder all other wires as shown.

This is what the completed mechanism should look like.  The decoder fits into the little pocket on the top of the frame.

Test run in both DCC and DC modes to verify the lights are all working the way they are supposed to and are synchronized with the direction the locomotive moves.

TCS Z2 in a Kato JR 117 series motor car

Well it's been quite awhile since I've posted any new installs.  It's not that I haven't been doing any, it's just that the types of installs I've been doing I had already covered.  But here's something new, how about a Japanese train.

This Kato set is typical of Japanese passenger trains.  It's a double ended train with a control car at each end and the motor is inside one of the middle cars.  So it actually takes 3 decoders to activate the head and tail lights and the motor.  In this post I'll install the decoder for the motor and will address the end cars later.

The plastic interior comes off by carefully prying off the outside tabs on each side on both ends.  Then pry the interior from the frame at the point shown in this photo to release the interior tabs.






I took a look at the decoder offered by Kato for their Japanese prototype trains but could not see how that would work with this model.  That decoder seems to be designed to use with some of the later releases that have a hatch on the bottom to install the decoder.  I settled on the TCS Z2 for this installation.

After getting the car all the way apart I was able to identify 3 possible locations that the Z2 could fit into.

A - There was room within the roof under the raised part but the wires would be very visible inside the windows.

B - There is a large pocket in the frame here but I was afraid of the decoder rubbing on the drive shaft.

C - I took the conservative approach and chose to just place the decoder inside near one of the ends.

To get the motor out, remove one of the trucks by releasing the 4 tabs as shown in this photo.  Then remove the assembly while pulling the drive shaft out from the motor.  The motor can then be removed while pulling it away from the other drive shaft.

The front and a rear ends to this car need to be established so that when we later add decoders to the end cars so the lights will be coordinated with the motion of the motor car.  To do this I referred to the instruction sheet that comes with the set.  These sheets are in Japanese but I have found the drawing shown below to be very helpful. The cars of this train are numbered 1 to 6 with the motor being in car number 3.  These types of trains are bi-directional and when they reach the end of their run, the operator walks to the control cab at the other end so there really is no front or back. For DCC purposes I like to think of car 1 as being the front.  The writing and arrows under the end cars refer to a destination.

Drawings like this one are in the instructions of each Japanese train set I have seen and are very useful in assembling your train in the correct order.


The orange and gray motor wires are cut at 2-1/2 inches.  These motors are identical to the ones in Kato's American prototype locomotives except there are no flywheels.  The brush assemblies are removed from the motor and these wires soldered to the brush caps.  Then the brush assemblies are re-installed in the motor.  The white magnet on the motor faces down.

After the decoder wires are connected to the motor brushes and the motor is re-installed, the plastic interior piece can be placed between the motor wires as shown here.  Then carefully guide the interior into place on the frame while guiding the orange and gray wires to pass through the gaps between.

The red and black wires can then be cut to the length needed to reach the exposed part of the contact strips and soldered there.  Red to the right and black to the left.  The decoder and wires are held in place with a small amount of adhesive.

Here is the completed motor car.  At a low angle the decoder should be barely visible.  To hide it further, the decoder and wires could be painted a color to match the interior.



OK, so that takes care of the motor car.  This train and ones similar to it also have end cars with both head and tail lights in each one.  that will be covered in a future post.

TCS Z2 in an Atlas SD35

As I model the Southern Pacific, many of my engines have the nose lights modeled but not lighted.  It's easy to add this type of lighting when installing a decoder using one of the pre-wired surface mount LEDs.





As this installation is otherwise very similar to several others I have presented, I will skip over some of the common points and focus more on what is unique to this installation. See my posts on the Atlas SD50 and GP40 for details of the basic decoder installation.

Once the shell is off a quick check of the mechanism indicates that there is room for a small wired decoder like the TCS Z2.

The original Atlas LED board is used after all of the modifications shown in this photo are done.  Note that an additional hole is made in the front part of the board for the nose LED wires.

This is also the time to replace the stock LED's with bright white LED's if desired.

While no modifications to the frame are needed for a standard installation, I did make grooves on the front of the left.frame for the LED and it's wires.

This photo shows what I had to do to the frame and the type of LED I used.

Here is a look at how the nose light LED is installed and connected to the LED on the board.  The ends of the wires will need about 1/8 inch of the insulating enamel scraped off before they can be soldered on the board.


Using a Z2 decoder and wiring this extra LED in parallel will mean that the nose LED will turn ON and OFF with the F0 function.

TCS Z2 in a Bachmann Spectrum 44 tonner

It's been a couple of months since I've posted anything but I have been kept busy with installs.  They've mostly been routine ones that I had already covered on this blog.   But recently I was asked to replace the decoder in a Bachmann Spectrum 44 ton switcher with a TCS Z2 or similar small decoder.

I was not very familiar with this model so I checked it out on the web.  It seems that Bachmann offered this model only in a DCC version and that no DCC manufacturer offers a replacement decoder.  Also on some of the forums there was mention of problems with programming this decoder.

This model uses the tested method of bumps on the frame / dimples on the inside of the shell to hold the shell in place.  It's a tight fit and after trying a few methods to get the shell off,  this was the one I found the easiest.

The trucks will come off fairly easy so I took them off first then placed a jewelers screwdriver between the fuel tank and the shell and gently pried.

Once the shell is off, we can see the original decoder board.  The decoder is secured to the frame with 2 small screws, one on each frame half.

The decoder has mostly surface mount components with a couple of coils on the bottom and what the instruction sheet called a thermal fuse link in series with the motor.

The way this component was installed in the motor wiring instead of on the board suggest to me that it may have been an after thought.

I made two custom LED boards from a two stock Kato LED boards that I had in my collection.  This photo shows the modifications I made to get what I wanted.

Here are the 2 new LED boards that I made from a Kato LED boards.  Don't know what engine it originally came from.  I wanted something with surface mounted LED's.  The new boards are secured to the frame by the original screws and provide track connection to the decoder.  I spliced the decoder wires onto the motor wires so I would not have to remove the motor.

Here's the side view of the finished mechanism.  One of the nice things about the LED boards I made was that they are single sided meaning that I don't have to worry about anything on the bottom shorting on the frame.  The space where the coils of the old decoder were could be used to add a bit of weight.

The inside of the shell of this loco offers an opportunity to add quite a bit of weight to this loco in the cab where the black plastic box that was attached to the original decoder had been.   I painted the inside of the cab windows a dark gray, then attached 2 layers of lead strip to the roof.   Another area where weight can be added is along the inside of the cab side walls below the side windows.

If the replacement LED boards, decoder, and wires are not interfering with the shells fit, the shell should rest on the parts of the frame that stick out as shown in this photo.

Here is the completed engine.  With the weight that was added it is close to the same weight as a stock Life Like SW type switcher and has about the same pulling power.

TCS Z2 in a Micro Trains FT

Anyone who has followed this blog will notice that I am a fan of TCS decoders and use a lot of their Z2 model.  I have found it to be a great decoder, small enough for many applications and robust enough for any N scale engine.  TCS does not make a board type decoder for the Micro Trains FT so I wanted to see if I could wire in a Z2 and found it to be a relatively easy install.

The first step is to remove the shell from the frame.  On the front of the A unit, remove the screw then pull the coupler out forward.

On the rear of the A unit and both ends of the B unit, removed the coupler and mounting frame together.

After removing the shell, the LED light board is exposed.  Just behind the board there is an indent in the frame that is large enough for a wired decoder.  Remove the black light shield and then the board. That's right, the frame won't have to be taken apart on this one.



The boards in the A units will have the LED along with a couple of other components.  Remove the two that are pointed out in this photo.  They were needed for the DC operation of the bright white LED but will not be needed for the decoder function output. 

The board from a B unit will not have any components on it at all so this step can be skipped.










I have found the quickest way to isolate all the parts of the board is to cut a notch on each side of the board through the two circuit traces.

This step needs to be done on the boards for both the A and B units.








Here are the lengths I cut the wires to. 

Blue, white, gray, yellow = 1"
Orange = 1-3/8"
Red, black = 1-5/8"








Kapton tape is best to use for insulating the frame but does not stick to the frame as well as Scotch tape.  I clean any oil off the frame of course, but then I use a layer of Scotch tape first then apply the Kapton tape.  It sticks very well to the first layer.

Connect all of the decoder wires as shown in this photo.  This can be done either before or after the board is re-installed in the engine.  The photo shows an A unit.  The B unit won't need the white and blue wires.

Special note on the B units

FT's were run with the B units oriented backwards in relation to their associated A unit and were often draw bared together.  This is noticeable by the two sets of ladders, the offset of the wheels and fuel tank, and the dynamic brake vents on the roofs of the ones that had dynamic brakes.  The PC board in the Micro Trains FT B unit is oriented in the opposite direction as the A unit.  This would have not mattered running DC but with DCC we must have a front and a back end to each locomotive.

Here is a prototype photo showing an A B set arranged this way.

This photo showing an A B set with the shells next to a pair of mechanisms shows what is going on.  This can be corrected by programming the B unit for reverse operation

CV 29 = 07 for 2 digit address
CV 29 = 27 for 4 digit address

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.