I’ve talked about the Track Tester, a GE 44-Ton Switcher, a few times. This unit – now having been given the nickname ‘Zebra’ due to its livery – was bought primarily to test the freshly wired layout and tell me if there are any problems that needed fixing – bad wiring, low power, something like that.
Unfortunately it never really lived up to the task. It was a poor, noisy runner out of the box, it would stutter along the track and stall most of the time. Initially I thought that this was due to track problems, but with time and research, the problems that could have caused such behaviour were addressed (to a degree – I am still looking for a way to keep my tracks clean for longer). But even when other locos were running fine, Zebra still acted up. With freshly cleaned wheels and on a clean piece of track, it would buzz but not move until the power was cranked up further – sound familiar?
Some more time passed, some more research was done, and I came to the conclusion that the problems were with the factory-supplied decoder. A number of forum posts regarding the exact same model appeared to confirm this.
Taking a closer look at the decoder, it had a very limited feature set. It supported basic speed tables, but out of the values for Vstart, Vmid and Vhigh, only the first one could be set. BEMF was not supported, which explains the behaviour described above. It was pretty clear that, if I wanted to get some use out of this loco, I would have to swap its decoder.
I already had one set aside, relatively simple decoder of the LaisDCC brand, but that one had to go into another loco. Initially I had my reservations about the brand and intended to keep the one decoder I had as an emergency spare. But when it performed decently in the BR 80, I decided to get another one for the Zebra. It turns out that LaisDCC released a slightly updated version of their decoders, so I figured I might as well grab one of those.
Replacing the decoder turned into a bit of work. Bachmann in their wisdom decided not to plug the decoder, but solder it to the loco’s PCB. They also used some sort of epoxy to secure the solder points – not the worst thing they could to, but it made my work a bit harder. Getting the epoxy off was a challenge, and eventually I ended up pulling the wires off with a courageous yank, followed by a bit of cleanup. Soldering in the new decoder was the easy bit, there was ample space between the solder pads, and the wires on the decoder are nice and flexible.
Back on the tracks, the difference was immediately clear. The loco now accelerates and runs smoothly, it behaves well in low speeds, and most of all, it’s quiet. With its old decoder, it made fairly loud, grinding noises, but now the noise level has dropped to where I’d expect it to be based on my other locos.
It still struggles with tracks that aren’t 100% clean, but so do all my other small locos. And that’s both a task and a post for another day.
The old decoder, soldered and glued to the PCB 
The PCB, cleaned up 
A last look at the old decoder before it goes into the bin
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