This installation is for Micro Trains line Z scale SD40-2 and features the MZA4 decoder.
Remove the body shell and handrails by gently pulling up on the shell. Remove the fuel tank.
Next, remove the screws highlighted in the image below and remove the original lighting board.
Next the frame posts need to be slightly modified before the MZA4 will fit in the frame.
The three pictures below show the "New"Style chassis before posts modification.
The three pictures below show the posts modification we did here at TCS. It will allow you to use MZA4 decoders in the new MTL Chassis style.
Using a dremel tool (on the SLOWEST speed setting) with a cut-off wheel cut into the notches in the frame and remove approximately half of the material between the notch and the outside wall of the post. The cut should proceed straight toward the outside of the frame and care must be taken to avoid making the notch any wider (.001"-.002" of extra cutting down into the post or up towards the top could prevent the decoder from fitting snuggly). The image below shows the completed modification.
Now reinstall the motor and place the MZA4 into the notches in the posts (as seen below), and replace the three screws that were removed.
Last the motor springs (not shown) must be looped through the small, motor pick-up holes (to the left of the of the frame posts above) in the decoder. Be sure that the springs will not contact the frame before replacing the shell and powering the locomotive.
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