Many DCC decoders have an option to allow them to work on DC. It's an option you choose via one of the CV's (often as part of CV29). If your engine had a "dual-mode" decoder and it's set to allow it to work on DC it should have worked fine. Most "DCC Equipped" engines are set up with dual-mode decoders.
However there are some issues I guess with "filtered" DC (like from an MRC Tech II or IV) vs. straight DC. The "filtered" DC apparently uses some AC pulses and that can confuse the decoder and cause problems.
So either the decoder you had wasn't set (or wasn't able) to use DC, and/or it had trouble with the MRC power pack output...or as has been noted, it was just wired improperly in the first place, although if it worked on DCC then that shouldn't be an issue.
Little wonder the decoder fried then. For precisely how NOT to install a decoder, read this.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Thanks Randy. I tried to do it last night but it turns out there is more work than that needed. The person who installed the decoder soldered the pick up wires to some tiny pieces of flat copper then soldered them to the motor pick up leads. The copper strip he soldered between the gray wire and the motor lead sepperated, so now I have to wait untill I get a soldering iron to do it all. Which is okay, the previous owner left a lot of extra wiring so when I redue it all (possible DCC w/sound just for funsies) I may just rewire the whole thing and not use such excessive wire tails. The wires for the lights were probably twice as long as the train itself from the pick up lead on the truck to the light bulb pick up, holy capoli. The previous owner just wrapped them in a loop and wraped the extra in black electrical tape. The good thing is all wire joints are soldered, none are completed by twisting the ends of stripped wiring together and then wrapping it in tape. Although if you twist it real good and wrap it real good that can be a really good temporary wiring fix. Don't ask, but it got me from point A to point B. And point C, and point D and point E and then back to point A. Even took me from point A to point F to get a decent wiring joint fix and then back to point A to get it fixed. Of course, I would NEVER use a quickie fix like that on my trains.
Sure, clip the wires from the decoder, connect the red and orange together, and connect the black and gray together. Track pickup will now go directly to the motor and the decoder will be bypassed.
This is what I get for monkeying with stuff. I have a Bachmann Plus B23-7 in Sante Fe trim that was hard wired with a Digitrax decoder, either DH121 or DH123 (I bought two engines at the same time but I can't remember which one had the 121 and which one had the 123). Anywho, I was using it on some DC (MRC Tech II) test track and ended up frying the decoder. Right now the shell is at the neighbors waiting to be "artistically" painted.
Can the Bachmann be rewired for DC control? My N scale has a PC board in it, do I need one of them to run in DC? It will be some time before I have anything decent up and running DCC, even longer time before I could buy a new sound equipped decoder, but can I still get this going on DC so I can still use it? I really don't want to get rid of it.