This installation is for a HO-Scale Bowser SD40-2 using a TCS EU821 Diesel Decoder. This install was performed by TCS.

The Bowser SD40-2 has 7 light functions, and with its 8 lighting functions the EU821 Diesel decoder supports all of them.

Note that this is same installation for both EU651 and EU851. The main difference between the two decoders is the EU651 is six functions and supports

Railcom. The EU851 is a eight function decoder that does not support Railcom.

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

HO-Scale Bowser SD40-2 prior to TCS EU821 Diesel Decoder installation.
The Bowser SD40-2 has 7 light functions, and with its 8 lighting functions the EU821 Diesel decoder supports all of them.


To start off this install, we must first remove the front and rear couplers and their housings. Once that is complete, the shell will lift off of the chassis.
With the shell off, we can now remove the 21-pin factory decoder from the original lighting board.

Now, simply plug in the EU821 Diesel decoder just like the original decoder. *Although, it is shown here with a speaker in place, this decoder and installation
is for 8 lighting functions and is not a sound decoder. For sound, please refer to the WOW121 installation found elsewhere on this site.

Replace the shell and the couplers and your Bowser SD40-2 with the EU821 is now ready to run!

Ideally we would add a Keep-Alive™ device to this installation, but there is physically no where to place it in this engine.
Besides that disappointing element, this is one of the easiest installations out there.

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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