LM-3S-21 Module compatibility with different manufacturers

[Espeelark]

I just installed my RailPro system in an Athearn RTR SW1500 switcher locomotive. Damn, it's tight in there! I shoe-horned the LM-3S-21 module onto the factory motherboard and also installed a speaker with some modification to the chassis.
ion.

Rob - I’d be interested in seeing photos of that install if you have them. I have an SW1500 on my desk right now doing a hard install. No progress has been made on it recently due to conflicting Summer activities. Thx!

[faithie999]

i have had to remove the shell of the LM a time or too, as well.  be sure to wrap the LM after removing the shell with Kapton tape to make sure it doesn't short out if it touches something.

i have also removed the circuit boards from loco's.  as long as you mark the wires, or can trace them out so you know which is which, the circuit board is superfluous when you're using RP.  if the loco in question is designed with incandescent bulbs, i would also remove those and switch to LED's with the appropriate resistors.

[gregeusa]

fathie999: I'm confused.

Since this thread is on the 21 pin version of RP decoder... if you remove all the circuit boards, do you wire in a new 21 pin plug so you can connect to the RP 21 pin module?

[sieggs1]

Hi Espeelark,

So here's the thing with installing the LM-3S-21 in the SW1500:

It's probably obvious that installing anything into this locomotive will be tighter than Tom Thumb's ass. I spent a good deal of time hacking up my brand-new SW1500 as I thought I didn't have a choice. I got the model WITHOUT the speaker or the default decoder from the factory because I knew I wanted to install a RailPro LM-3S-21 and my own speaker.

I had to hack up the frame a little in the front where the speaker would have come from the factory. I had to use a Dremel and file down the inside of the locomotive shell where the tabs are underneath the two exhaust pipes since this is where the LM-3S will sit. I also wanted to install Ring Engineering's version of keep-alive which is their PBM-2 module. But the only place to fit it would be inside the cab and that means removing the interior detail. It also would have been obvious that there the PBM-2 was in there through the windows.

After knocking most of the details off the shell (I will re-glue them later), I was getting frustrated that I couldn't fit the shell back on.

So I have a new approach.

I ordered a Decoder Buddy Mini from Nick Santo at NixTrainz. It will replace the factory motherboard as it is much smaller. I plan on using a few strips of styrene to build a shelf for it between the flywheels. This way, the LM-3S will sit much lower on the chassis and it might not have been necessary for me to modify the shell. Then I will see if there is room outside of the cab to install the PBM module.

I should have the Decoder Buddy Mini next week and I can approach the install from this angle.

I have a feeling that the Decoder Buddy Mini was the route I should have gone in the first place without hacking up my locomotive.

Well, you live and you learn.

I will report back one I have received the Mini and how it worked for the install.

Rob

[gregeusa]

OK, that makes a lot more sense to me... ripping the motherboard out and NOT "replacing" the MTC21 plug would have made it impossible to connect in any "safe" way to the 21 pin decoder... in my opinion

Greg

[LVRR1856]

I just ordered a small drill press and a milling table, figured I invested a few bucks in the RP system and definitely know to fit them into most HO locos .... "Some Milling Required" - this should help the process. I've seen many dcc installs cutting frames and weights as well - so, to be expected.

[faithie999]

fathie999: I'm confused.

Since this thread is on the 21 pin version of RP decoder... if you remove all the circuit boards, do you wire in a new 21 pin plug so you can connect to the RP 21 pin module?

shame on me!!  i responded too quickly and overlooked that significant detail!  i see that in a subsequent message another member gave the right info.

sorry!

Ken