This installation is a TCS T6X installed in a HO Scale MTH SD70ACE. Installed by A.C.E.

Important Soldering Tip:
Please do not use any flux either liquid or paste on the mother board. It will damage it. Use only Rosin core solder approved for electronics use.
We recommend to use only Kester "44" rosin core, SN63PB37, .015" diameter, part number 24-6337-0007.
This can be ordered from Techni-Tool under Techni-Tool part number 488SO157

A T series long harness (five inches) was used.

We recommend using a foam block as shown below for doing decoder installation work. They are a great aid in holding the loco in place and help to prevent damage to the detail parts. They are available through Walthers.

The first step is to remove the shell from the chassis. This seems like a difficult task it first but we found it is really quite easy once you know how. The instructions that come with the loco are very good. To remove the shell you must do two things. One: remove the handrail from both sides of the loco. Also remove the handrails on the front only where they attach to the loco shell. We found it was easiest to remove the handrails on the front with tweezers. The handrails on the side we did by hand. Gently pry up wards on the hook at the top of each rail post as you push the wire rail out of the hook. The rail will come out very nicely this way. The rail itself is metal wire. We found it to be quite rugged. There was no worries about bending or breaking it.

Two: you must remove the wheel sets and spread the truck frames apart on both sets of trucks. This will reveal the tabs the hold the shell onto the chassis. Refer to the instructions that come with the loco to do this. This seems like a intimidating task but it is not. It took us all of two minutes to remove the wheel set, spread truck frames, pry the tabs and the shell was off. Once we had the shell off we put the wheel sets back in place right away.

Photo below shows wheel sets removed and truck frames spread apart. This reveals tabs to remove shell. See next photo to locate tabs to remove the shell.


Photo below shows tabs that hold shell on. Pry outward on the tabs with small screwdriver to free the tabs and remove the shell.


After the shell is off put the wheel sets back together and remove the NMRA shorting plug and the two small jumpers located on the sides of the lighting board.

Photo below shows NMRA shorting plug removed. Also Ditch Light and number board jumpers removed.

It is very easy to hook up the blinking ditch lights and number board lights. No resistors or special wiring needs to be done. MTH got this right! If only other loco manufactures would follow this example it would be great! Simply attach the function wires to the appropriate tabs and the installation is done.

Photo below shows T6X decoder installed with a TCS 5" long harness. Notice violet pink and brown wires soldered to the tabs on the MTH light board. We used violet for the number board lights. Brown for the left Ditch light. Pink for the right Ditch light. Program the following CV's as follows and you will have complete control of the operating ditch lights and number board lights. Set CV39 and CV40 = 4, CV53= 42, CV54=43, CV52=32, CV36=16. This sets button 3 to operate the number board lights, button one to turn on/off the ditch lights, button two will blink the ditch lights.


Photo below shows the extra wire taped down using 1/4 inch Kapton tape. It is good to keep the installation neat. Tape down the decoder and wire in place. A 5" long harness was used for this installation.

MTH did a nice job with this loco by including the operation of the ditch light and number board lights by simply hooking up the decoder function leads to supplied tabs on the loco

lighting board. Every installation should be this easy!

Other solder tips: When stripping wire, only strip a tiny little bit of the insulation. Strip no more then a 1/64 of an inch. When the wire gets tinned with solder the insulation will shrink back more. Try to not expose any more wire then half the length of the solder pad at most. In no case should solder or exposed wire wire ever be outside the boundary of the the solder pad you are attaching a wire to.
Click here for important information on properly Stripping and Tinning wire

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