Bachmann Spectrum USRA Light 2-10-2

Scale:
HO Scale


This installation uses the following decoder:


The installation is for HO Scale Bachmann Spectrum USRA Light 2-10-2.This installation uses the TCS T1P-SH digital decoder, and was performed by A.G.

Update: TCS now recommends using the DP2X decoder for simple plug-and-play installation.

The three upper pictures show the locomotive prior to the decoder installation. The TCS T1P-SH will be fitted into the locomotive's tender.
The three upper pictures show the locomotive prior to the decoder installation. The TCS T1P-SH will be fitted into the locomotive's tender.
Here is a picture of the tender where the decoder will be installed.
Here is a picture of the tender where the decoder will be installed.
There is a one Phillips screw that holds the tender's chassis and its shell together - Remove the screw and gently lift the shell off of the tender's chassis.
There is a one Phillips screw that holds the tender's chassis and its shell together - Remove the screw and gently lift the shell off of the tender's chassis.
Here is a picture of the original light board with original Bachmann DCC decoder.
Here is a picture of the original light board with original Bachmann DCC decoder.
Remove the original Bachmann DCC decoder that came originally installed with the tender.
Remove the original Bachmann DCC decoder that came originally installed with the tender.
There are two capacitors that need to be cut out. There are two capacitors across the motor circuit that drastically affects the speed curve when using a Quiet Drive decoder. It causes an over-speed problem. It must be removed from the circuit. Do this by simply cutting the capacitor out . The capacitor is typically yellow and has a marking of 105.

Technical explanation. The capacitors are placed in the circuit by Bachmann for the purpose of reducing the possibility that electrical noise generated by the motor when running would interfere with a TV or radio or cell phone or possibly some other electronic device. All TCS decoders have this capacitor  built into the decoder and there for external capacitors are not needed.  The TCS decoder is tuned to work with its own  internal capacitor in operation. With external capacitors applied in the circuit the result is a de tuning which results in poor speed control. That is why the Bachmann applied capacitors  need to be removed. The internal decoder capacitor reduces the possibility of electrical interference so there is no harm in removing the external capacitors.
There are two capacitors that need to be cut out. There are two capacitors across the motor circuit that drastically affects the speed curve when using a Quiet Drive decoder. It causes an over-speed problem. It must be removed from the circuit. Do this by simply cutting the capacitor out . The capacitor is typically yellow and has a marking of 105. Technical explanation. The capacitors are placed in the circuit by Bachmann for the purpose of reducing the possibility that electrical noise generated by the motor when running would interfere with a TV or radio or cell phone or possibly some other electronic device. All TCS decoders have this capacitor built into the decoder and there for external capacitors are not needed. The TCS decoder is tuned to work with its own internal capacitor in operation. With external capacitors applied in the circuit the result is a de tuning which results in poor speed control. That is why the Bachmann applied capacitors need to be removed. The internal decoder capacitor reduces the possibility of electrical interference so there is no harm in removing the external capacitors.
Picture of the capacitors after the clipping process.
Picture of the capacitors after the clipping process.
Place our TCS T1P-SH into the DCC socket exactly as shown above. Plug in the decoder so that the Orange wire lines up with Pin #1 of the socket. Pin #1 will be designated with a "1" or a small arrow/chevron. 
Place the shell back, reinstall the Phillips screw and we are ready to go!
Place our TCS T1P-SH into the DCC socket exactly as shown above. Plug in the decoder so that the Orange wire lines up with Pin #1 of the socket. Pin #1 will be designated with a "1" or a small arrow/chevron. Place the shell back, reinstall the Phillips screw and we are ready to go!

Important Soldering Tip

Please do not use any flux either liquid or paste on the mother board. Over time, the acidic properties of liquid or paste flux will begin eating away at the fiberglass PCB and will damage it. Use only Rosin-core solder or no-clean flux approved for electronics use.

TCS recommends the use of Kester "44" Sn63 Pb37, .015" diameter Rosin-core solder. Kester part number 24-6337-0007.

You can order this solder from the following retailers:
Digikey - PN:KE1110-ND
Techni-Tool - PN:488SO6775

Other solder tips

When stripping wire, only strip a tiny little bit of the insulation. Strip no more than a 1/32 of an inch. When the wire gets tinned with solder, the insulation will shrink back more. Try to not expose any more wire than 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