This installation uses TCS AMD4 decoder and is for N-Scale Atlas GP40. Installation submitted by Alexander Clark.
Gently remove the 4 handrail ends from the cab by easing them out of their holes, gently pull the body off the frame by gripping it and the bogies, the body may come apart from the walkway when pulling apart, pull the fuel tank from the frame.
Mark the bogies and frame halves and note their orientation, remove the 2 screws securing the frame halves and gently prise the frame halves apart on the top just enough to release the original circuit board. Remove the led shrouds from the original board and fit to the AMD4 board. Test fit the AMD4 board into the frame lugs, they should be an interference fit and not to tight or loose. If it is too tight there are 2 options,
1- VERY GENTLY prise the lug apart, if using this method it is safer to repeat the operation several times rather than overdoing it the first time as there is a risk of snapping off the lugs
2 - Completely strip the frames and move the motor and gearing well away from the work area and using a needle file widen the gap, ensure the frame halves are clean before refitting the motor. If it is too slack, build up a little solder on the offending pads.
When the board will fit snugly into the lugs place a piece of Kapton tape on the frame where the motor tabs pass through the frame just below where the board will fit and rebuild all the parts in reverse order of strip down, when securing the frame halves with the screws do not over tighten them as they will cause the bogies to bind. Using a multimeter, test across the frames to check that they are no shorts.
Test the locomotive for operation and adjust any CV’s as required, refit the body and enjoy.
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 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