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I have a question about the Rivarossi FEF 3 locomotives. I have two of them ( 5428 and R 5473 ), and would like to know if they run well enough to invest in a couple of Digitraxx sound decoders? Any info would be greatly appreciated.
How old are these locos? I have a couple of AHM/Rivarossi diesel models from the 70's that would turn a decoder into something resembling an overcooked potato chip. A lot of the older motors require a a lot of power just to get started. The oldest loco I tried putting a decoder into was an Athearn SD45 that had the old black ring magnet motor. While the decoder survived the experience it couldn't put out enough power to get the motor up past a very slow creep. I'm talking about make a mark and come back in an hour to see if the loco moved. It ran great on DC but on DCC it just required too much power. After I changed the motor out with a modern Athearn motor the same decoder runs the loco just fine.
If you want to see how well it would run on a decoder, why not dig into one and install a regular decoder? Use a 9 pin JST harness and when the time comes you just have to pop off the old decoder and plug in the new and install your speaker.
There shouldn't be any problem then. I have HO locos that are 20+ years old that are running just fine on Z Scale 2 function decoders (motor and lights). My decoder of choice is the Digitrax DZ125. It's tiny and can fit in very tight spaces. I've put them in locos ranging from small switchers to big SDP40F's.
Now just because a loco has a newer type motor doesn't make it safe for a decoder install. Get it checked to see what the stall current is. That's how much power does the loco pull before the wheels slip. If it's above 1.5 amps you're going to need a decoder that can stand up to 2 amps and even then it could still fry. That rating precludes the use of most motor/sound decoders. If it's below 1 amp most any HO or N and the heftier load Z Scale decoders can handle it. Decoders with motor and sound control work well in this range as well. Keep in mind that many sound decoder installs in locos not made for them usually requires the removal of some of the weight. This can and will effect the pulling capability of the loco. I would suggest putting the speaker in the tender on a steam loco.
