HO scale MLW M420 Locomotive Support

HO scale MLW M420 Locomotive Support

Important DC Advisory

Do NOT use cheaper "train-set"-type controllers with any of your Rapido locomotives. Several models of controller are notorious for voltage spikes and they WILL destroy your locomotive. There is no “if” about it. We will try to help you if we have the parts, but we are not responsible for locomotive damage due to voltage spikes in your power supply. As well, we will not repair any Rapido locomotive damaged by any "train-set"-type DC controller unless you have retired the controller. Otherwise the damage will likely reoccur. “Train-set”-type DC controllers should not be used with any modern model locomotives.

General Problems and Inquiries

If your model arrives with damage or there is any other issue, the best thing to do is to contact our support team. They take care of all of our warranty repairs and they are all swell guys. The toll-free number is 1-855-LRC-6917 (1-855-572-6917) (outside North America, + 1 905-474-3314 or 905-474-3324). You can also email us – click here.

Squeaky Drives

We've recently gotten some comments about some M420s making a squeak as they operate. This is due to the axle ends not having enough lubrication.

Thankfully, this is a pretty easy thing to fix. We suggest adding a drop of a plastic-compatible medium weight gear oil to the ends of each axle where they contact the truck sideframes. If you can find one with a needle applicator, you don't even need to disassemble the trucks.

Volume CVs

Before you manually change any of the volume control CVs, set the master volume to the level you are comfortable with (or leave it alone). THEN, set any individual sounds.

To do so, you must set CV 31 to 16 and then CV 32 to 1. CV 31 and CV 32 are used as index selection registers and if you don’t set them first, unspeakable things may happen to your unit. You must set the CVs every time before changing any volume CV setting. Or just use a LokProgrammer...

Rear Light Functions

The manual for the M420 has some information regarding operation of the rear light that is missing. Below is the expanded and corrected list of functions regarding operation of the rear light.

F12 "Switching Mode"

If you press F12, the headlight and rear light will both be on dim. This is appropriate for switching operations, which would be common in yards and terminals.

F13 "Rear Light On/Off"

Pressing F13 will toggle the rear light 'on' and 'off'.

F15 "Model Train Mode"

Pressing F15 changes the front and rear lights on your M420 to operate "the old fashioned way". When your M420 is set to forward, your headlight will be on. When it is set to backwards, your rear light will be on. Just like the good ole' days of straight-wired DC models, only better!

Function Issues on Digitrax Systems

If you operate with a Digitrax DCC system and your DCC loco does not seem to be responding as it should, please try the fix described below before contacting us. It may save you some time and aggravation! Apparently, some Digitrax systems store the address of every single loco that they’ve ever used on them, and regardless of whether the loco was dispatched or not. Once this memory fills up, any new locos that attempt to be used by that system exhibit very unusual behavior including non-working functions and odd responses. The solution to this is easy. All you need to do is clear the memory in your system. This is done by clearing slot #36; see the instructions below. Once you’ve done this, you’ll likely find that your loco operates exactly as you expected it should. General Instructions for Closing Command Station Option Switches (for specific instructions for your command station and throttle, see the instruction manual for your equipment):

  • On the command station, set the MODE toggle switch to the OP (center) position.
  • Using your throttle go into Switch Mode
  • Enter the Option Switch number you wish to change (in this case 36).
  • Press the “c” key on the throttle.
  • You will hear a beep.
  • On the command station move the MODE toggle down to SLEEP then back up to RUN.
  • Using your throttle, turn Track Status back on.

For more information, see this page from Digitrax’s web site.

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