Thursday, December 7, 2023

The Atlas Classic RS-3 and the ESU "Drop In" Decoder (#58921) - A Cautionary Tale

I was excited to finally get started on my New Haven DERS-2c #529 project - click here for why and what all I got in preparation.

Unfortunately, I've run into a major roadblock: The ESU "Drop In" decoder, with integrated Power Packs (#58921) does not actually "drop in" to the Atlas Classic RS-3 model I wanted to convert. In fact, it doesn't fit at all as designed.

Read on to see why - and hopefully to avoid the same (major) mistake I made . . .

ESU photo

ESU's Loksound 5 DCC Direct with Integrated Power Pack decoder (#58921) promises a relatively easy DCC conversion, with the bonus of having "keep alive" capacitors already installed on the motherboard. While not a true "drop in" that doesn't require soldering (like the version without the capacitors (#58821)), both decoders are touted as an "easy" board replacement. I can't speak to the 58821, but I know that's not the case with the 58921 - at least not in an Atlas Classic RS-3.

When you try to attach the board to the loco as indicated, you discover that the slots are a little too close together to allow an easy install. Note the slot on the left. . .

The spacing between the slots is a good 16th to 3/32" too short.

But the board is supposed to fit, right? Maybe I'm being too picky?

Thinking so, I decided to press a little harder . . .

That was a mistake . . .

A BIG mistake!

Note that the leg of the capacitor didn't break at the solder joint - it actually pulled the solder pad up with it(!!)


Fortunately, I hadn't gone through the trouble of soldering all the wires to the board (which the 58821 doesn't require. Just sayin'). Unfortunately, I didn't check with anybody about alternative mounting suggestions or pro tips for using the 58921 before attempting to install it.

Which is where I hope this post is helpful - not only to warn you about this board if you're trying to install it in an Atlas Classic RS-3 (I know many of you have them), but also to avoid the mistake I made - and to pass along an installation pro tip. At least it's how I plan to proceed . . .

First though, this board is on its way back to ESU. To their GREAT credit, after hearing my story they've agreed to consider replacing it under warranty. I'll let you know how that works out.

Regardless, since I really want the capacitors, I've since gathered a lot of input on how others have installed this particular board and the consensus is that they snip off at least one of the mounting clips (preferably the one closest to the capacitor) and use double-sided tape to attach that end of the board. I'll probably also use some Kapton tape to hold it all down.

So the conversion of this Atlas model into NHRR DERS-2c #529 is sidelined for the time being. But hopefully, it'll only be a temporary setback and I'll be able to continue the install soon. Fingers crossed!

PS: If any of you reading this have actually installed the 58921, please let me know. I'd really be interested in learning how you did it.


  1. A real "ooohh, fuuuuuuddggge" moment. I picked up an Atlas Classic RS1 a while back and went down the rabbit hole trying to outfit, and landed on the build that ScaleSoundSystems did ( - dual speakers? Heck yes!). In doing the research, I got the feeling that there were multiple variations of the Classic RS1. I'm not going to try to recount them, but as I compared what I bought to images I found online, I saw a few variations. And I do know there is a Classic and a Master. I wanted the same stay-alive configuration as you so I'm interested to see how this goes.

  2. Thanks for stopping by Ben! I just got the replacement board in the mail from ESU - brand new board, no questions asked. Looking forward to installing it, but now likely won't get to it until after New Years. Happy Holidays and stay tuned!