QSI"Stationary" Sound Decoder?

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I have in my possession a first generation QSI sound decoder without an upgrade chip that I would like to use as a stationary decoder mounted underneath the table and used for background sounds. My question is, does anybody know if I need to put a load, like a resistor across the motor leads on the board since there will not be a motor attached? The throttle will be ramped up and down occasionally. My intuition tells me no but, I'd rather find out from somebody with some expertise in this arena rather than risk turning my decoder into an effective but short lived smoke generator in the event I'm wrong.

Thanks in advance for any help, advice, thoughts, suggestions and/or prayers:rolleyes: on the subject.


Well-Known Member
Staff member
I put a QSI decoder with a dead motor driver in a dummy loco. It worked fine in that capacity, so I imagine one mounted under the layout would do the same.
Let us know how it works out, I've thought of doing that also...
Oh, I'll let you know how it works out Rico. In the meantime, if you smell an electrical burn you'll know I fried it. I've got to go out on assignment for a couple of weeks before I can get to it but I'll put a post up and let you know what happens.
Gotta tell ya guys, I really like this forum. I put up this thread tonight and already I've gotten some good response. That tells me it is an interactive forum with a lot of guys scanning it and ready to help.

I had this same thread plus another up in a different forum that shall remain anonymous. In five days I got no response on one thread and attitude in the other. I have unsubscribed to that forum and will stay close to this one. It takes a lot of great guys to make a great forum.....and this is a great forum.


Master Mechanic
Your right, it wouldn't hurt. But the problem is I don't know how to determine what wattage size resistor or what ohm to use.:rolleyes:
Digitrax has a decoder tester called a LT-1. It came with my Digitrax set, but is available separately. They have a resistor in the set to act as the motor during testing. It is a 100 OHM 2 watt resistor. I would think that it would work just fine.
Wow! You are the go to guy Cj. Just the information I needed. If Digitrax stuck them in there for motor load compensation then, if for no other reason than insurance, I'll do the same. Found 5 for 3 bucks on eBay so here we go.

I am in your debt Cj. You have been most helpful and I really do appreciate it, not to mention all the anxiety you have saved me. You do this forum proud. And next time I need advice on changing out the micro processor on my computer's mother board I'll know who to contact.:D

Ah ha! Now that has merit. Didn't occur to me. That gives me all the more reason to install the resistor. I would want to be able to read CV's back from this decoder. Good call. Although I am no electronic engineer, it seems to me years and years ago either reading or hearing someplace that some solid state components had to be in a circuit or they would blow the output transistors. Maybe that was just an old wives tale but it has always stuck with me and I get nervous whenever I leave something open in a circuit.

Appreciate you throwing your two cents worth in the pot although I would consider it to be more like two greenbacks worth, especially in this day and age.

I just love this forum! All these great ideas, thoughts and helpful suggestions. It's like they say, modelers helping modelers. What a great hobby! Just hope I can pay back somewhere down the road.

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