The installation is for HO Scale Bachmann Spectrum USRA Heavy Mountain 4-8-2 Steam Locomotive.. It uses TCS DP5 digital decoder and was performed by A.G.

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

Here is some pictures of the beautiful Heavy Mountain Steam Locomotive from Bachmann prior to the TCS DP5 decoder Installation.


You will need to unplug the two (2) wired connectors between the locomotive and tender, from the tender.


You will need to turn the tender over and remove the front phillips head screw.


Remove the rear phillips screw and lift the tender from the drawbar.


Once the tender shell is removed you will see a small pcb board mounted to the chassis. On top of this board is an 8 pin socket with a small jumper pcb plugged into it. Remove this jumper as this is where the TCS DP5 decoder will plug in.


Here is a close-up picture of the original light board where 8 PIN Plug can be seen.


See these little yellow two legged capacitors next to the 8 pin socket? You need to cut one of their legs (as shown in the picture below).


Use small piece of Kapton tape on the side of the DP5 Decoder to make sure it will not short to the parts on the original light board.


Once the shell has been reinstalled connect the tender back to the locomotive. The Heavy Mountain runs nice and smooth with this decoder and installation is real easy!



Because of the fact that this locomotive has a flicker light in the cab some programming issues could occur. If you are experiencing any programming difficulties, remove the engine from the track, disconnect the 2 PIN connector that is placed between the tender and the locomotive. Place the locomotive back on the programming track, do the necessary programming. Remove the engine from the track again, reconnect the 2PIN plug and you are ready to go. This programming procedure is true for all Bachmann steam locomotives equipped with flicker light. See some pictures below for the details.

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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