into a Rivarossi HO 4-8-4
by Kevin C. Ceroky PE
I have a newer HO-scale Rivarossi 4-8-4 with an NMRA 8-pin socket underneath the sand dome. Seems like a no-brainer, but none of the HO scale decoders fit, no way. I contacted Hornby, who markets Rivarossi now, and they re-directed me to a hobby shop in Ohio. Those folks said to us an N-scale decoder. I used a Digitrax DN163-PS. It fits nicely, and has the amperage capacity for the loco. However, I smoked the first one. I had first bought an HO decoder since it’s an HO locomotive, and needed to take off the boiler shell. The factory wire joints weren’t quite as craftsman-like as they could have been, and some of the leads had strands sticking out that had not at all been soldered. Testing the bare chassis with a VOM (you can use a digital multimeter) went fine, no shorts. In the process of testing the bare chassis with the decoder, then moving things a bit to put the boiler shell back on, the wires moved, shorted, and toasted the board. So, the lesson is to examine these joints to the NMRA socket with a magnifier to check for stray strands.
Hope this helps someone!
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