http://www.litchfieldstation.com/xcart/product.php?productid=999002742&cat=206&page=1 We were playing with the MRC sound decoders this week, tying to install it in a milled frame, and ran into problems. Per directions, we used wires to attach it to the motor by soldering it to the tabs. Before we installed the board, with it hanging out in mid-air and not touching the motor frame, we hooked on alligator clips to the rails and decoder to see if it would work. Runs like a charm, and sounds great too! Then, we put the decoder into the frame and closed it all up, BUT the wires bent the board up slightly because there is only one mounting slot to the aft of the loco, even though there are two tabs on the circuit board. The board is extremely thin, so much so we had to add solder to the pads to get it to stay put. I mean really thin, almost floppy when you wiggle it. Well, we put it on the rails and it was pretty flakey, worked for a bit and then stopped, then go, and the NCE controller would reboot over and over. The weird thing is that there was no smoke! Shorts cause smoke, usually making the little black boxes on the board disappear, so I don't think the board was shorting out. After disassembling and using the alligator clips again, the decoder worked fine. We're still cogitating on this, but I think the problem is that the MRC board may be susceptible to bending! Could this be the problem with the MRC decoders that is reported in many forums? I ordered two more for further experimentation...
I have installed 4 of these now into Kato SD40/45 non-PNP frames and haven't experienced any of these problems. But you didn't mention what make of engine it was. If the wires are pushing up the board, how about shortening them and trying that and see if that is the problem.
Not neccessarily. Shorting the track will make the control box (circuit breaker) trip without causing damage, provided all the wiring is up to scratch. A short in the loco achieving a similar effect could do likewise. It is also possible for a decoder to develop a short without smoke production. Smoke is a good indicator of a major problem, but its absence does not mean there isn't one. It does sound like an intermittent short. As mavrick says, first check your wiring and all possible metal-metal contact points. If stranded wire is involved look for any 'whiskers' that may have escaped at the ends.
this sounds like the problems other and myself are having with the MRC 1644 sound board. Your issues sound exactly like mine. I took a brand new kato AC4400CW that had a digitrax decoder in it and it ran great. I installed the 1644 and could never get good operation again even on a brand new length of track. This to be a decoder issue or why would the "standard" decoder work fine both before and after? (I have an NCE system also) I don't know what to tell you mine are all back at MRC not a word out of them yet. I wish i would have waited until revision 2. SD
Intermittent sound suggests to me intermittent contact between the decoder and the speaker. Somewhere along that conduit is your problem...perhaps even a wire to the speaker magnet.
