This installation documentation is for the HO Scale Rivarossi 3 Truck Heisler. This installation uses the M1P-1" decoder, and was performed by A.G.
The locomotive is shown here as a courtesy of Bill Meyer.
The pictures above show the locomotive prior to the decoder installation.
Using a phillips screw driver, remove the screw inside the stack.
Remove the whole stack assembly as shown in the picture above.
Gently remove the piping from the air tank and lift the front of the boiler upward to disengage the wire braces that holds it to the frame, then pull forward to release the pegs and handrails from the cab.
Water tank picture. The hatch needs to be removed.
Remove the water tank hatch as shown in the picture above.
Using phillips screw driver remove the screw that holds the bunker to the chassis.
Remove the small air tank from the right front of the cab, under the running board.
Remove the front screw (marked in red) then lift the cab and bunker off the frame.
lift the cab and bunker off the frame.
Here is a picture of the disassembled engine where you can see all parts that need to be removed before the decoder is installed.
Here is a picture of original light board where you can see NMRA plug.
Remove the 8-pin "dummy" plug as shown in the picture above.
The picture above shows 8-pin NMRA socket where Pin #1 is marked.
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.
Here is a picture of finished decoder installation. Black electrical tape was placed over the decoder so that it can not be seen through the cabin's windows. Reverse these steps to reattach the parts.
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
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