Stayin’ Alive!

Installing a SoundTraxx Current Keeper II on a 2014 Athearn Genesis GP7 Locomotive

Pictures from June 9 thru June 28, 2021

I was inspired by a discussion on the Proto-Layouts Group.io site regarding the addition of a keep alive circuit on DCC equipped locomotives. The track work at the Niagara paper mill on my layout is difficult and there are many poorly connected turnout frogs and other gaps that make switching that industry less than satisfactory. I started juicing all the frogs and cleaning track but I still wasn’t getting the results I wanted.

The CNW GP9 No. 1155 is one of the newer locomotives I’ve purchased so I ordered a Soundtraxx Current Keeper II hoping that maybe the decoder on this locomotive would be equipped with a socket to plug in the Keep Alive and I would be off and running.

The Current Keeper II arrived and so I disassembled the locomotive. Alas, no socket. I would have to figure out how to solder the new capacitor circuit to the decoder board myself.

The first thing I had to figure out was what decoder shipped with these locomotives in 2014. The Soundtraxx website has some information to help identify this, but my results were inconclusive. I finally landed on Tony’s Trains website. The site was very helpful in helping me deduce that I was working with a Tsunami TSU-GN1000. This turned out to be very helpful, but the wiring diagram on the site did not work.

The next step was to set up a programming track on the layout so that I could read the values currently on the decoder. I gapped the locomotive track at the Antoine yard and installed a DPDT switch on the control panel to alternate between the programming track and regular DCC operations for that track.

Even if I could figure out how to connect the Current Keeper, I also had to find room for it. There seems to be a piece on the front of the locomotive that is removable for this very purpose.

That piece seems to be there to add weight, but the pickup wires from the front wheels run through it. They had to be disconnected in order to remove the piece. The Current Keeper is a little larger, but we might be able to sneak it in there.

Looks like it might work!

They look awfully close to the same size.

I decided to go for it and try the method recommended by Tony’s Train Exchange. After connecting the wires as shown, I could not read values from the decoder on the programming track. When I disconnected the ground, the decoder behaved as usual. I was concerned about soldering on the decoder board, but so far I had not ruined anything. Back to the drawing board.

I searched for additional hints, videos, anything to try to figure out how to get the Current Keeper to work. Luckily I stumbled on to this site. It contains specific notes on installing a keep alive circuit on the TSU-GN1000 and a plethora of other useful information provided by someone who thoroughly understands the electronics behind all of this. It includes the following diagram.

I wired up my decoder using these instructions and it worked!

Maybe someday I’ll upgrade my WordPress account so I can show you the video of the newly wired chassis navigating the paper mill trackage without stalling. It was a great moment on the ore lines!

I thought I was finished but there was more fun in store. As I went to reassemble the locomotive, I noticed one of the small light bulbs was not sitting in the bezel properly. As I worked to get the bulb to sit properly of course I smashed it with my tweezers. I called my local hobby shop (G & G Hobbies in Griffith) and they gave me the number to Athearn (310) 763-7140. After providing them with the part number off of the diagram in the instructions they were able to ship me a four-pack of these bulbs. I ordered them on Thursday and they showed up on my door on Saturday. Impressive.

I wired the new light bulb with the old and secured the bulbs from the inside of the shell with canopy glue. I also taped down the wires with some heat resistant tape.

Still I was not finished. Because the realistic cab takes up some room, it took three tries to get the chassis back on without pulling the Current Keeper II wires off of their mounts on the two anodes. Finally I routed the wires between the connectors at the front of the decoder and managed to get everything back together without damage.

I was very concerned at the beginning of this project that I would ruin the decoder and damage the locomotive. My skills around electronics are minimal but I can follow directions. Happily this project was successful. The keep alive circuit makes tooling around the paper mill a breeze! Let’s run some trains!