Here are two images. The first is a Kato F7 mechanism (top) and an F3 mechanism (bottom). Note the gray plastic clip beside the flywheel holding down the motor contacts. I don't see any differences between the two... do you? The second is an F7 mechanism with a Digitrax DN163K0B decoder installed... a decoder Digitrax says is just for the F3. The loco didn't run reliably, so the fellow who did the install for me soldered the motor contact tabs down to the decoder. This was before I started doing my own installations.
The Digitrax DN163K0b is indeed compatible with the F7 A/B units, I've just done six of these over the last few weeks. I've noticed a tendency for the install in some to be slightly unreliable. Sometimes working with shell off but not with the shell on. Also in the A unit the black plastic mask that prevents the LED light spilling into the cab area can also cause the decoder board to flex slightly, and lose connectivity. I've actually found using something slightly thicker than the supplied kapton tape provides enough uplift on the decoder board to maintain contact, though if you're not careful use too much the motor tabs are sometimes difficult to trap under the grey plastic clip. Still I have six running successfully now. I may go down the soldered route too if the problems resurface over time - has anyone else had this problem, and what has been their solution?
I have soldered a bunch just like the photo above. One thing I have noticed about Digitrax PnP decoders, such as the DN163AO, is that the decoder board is thinner than the factory light board. This results in a sloppy fit. The 4 contacts on the decoder need to be built up using solder to fit the frame. When I first began installing decoders, the Digitrax decoders fit just fine. Why are they thinner now? To save money?
Thanks guys! Useful info. I have an F7A, two F7Bs, and that F3 still to do. Was thinking about the new MRC sound decoder ( MRC - DCC Series - N GAUGE SNAP-IN SOUND DECODER FOR KATO F3, Item: 0001658, TRAIN CONTROLS/DCC) for one or two of them. This is the first plug-and-play decoder I've ever seen with the speaker mounted directly on the board. My concern is that I've heard some negative comments about MRC decoders on this forum. I'm concerned about consisting with the F7 that has the Digitrax decoder. I don't have any experience yet with DCC consisting. Has anyone made consists using locos with different brands of decoders? I'm concerned about matching speeds between the locos without having to do a lot of reprogramming.
Lownen; While I have had no problems with my F3 ABA set, my PA's, E8's and P42 were another story. Since the decoders are similar, perhaps my solution would work. The problem I found is caused by wrapping kaptan tape around the brass pickup strips. This causes motor contact issues because the strips fit so tightly in the motor saddle. First thing I did was to eliminate the need for tape by notching the strips on the outside where they would contact the motor tabs. About halfway will do. Be careful, as the strips are somewhat fragile. Then, add a little model cement when you put the strips back in to hold them in place. Second, before installing the decoder, tin the motor contacts lightly(this comes from Dave at digitrax). One last thing. Sometimes the clip will fit better one way than the other, so you may need to just spin it around. I have done six locos this way, and every one runs great. Hope this helps. John
It's probably not going to work well mixing sound and non sound decoders without some tweaking. The sound decoders have a startup sequence and delay before they start rolling, just like your E7's. I'm sure there is a way around it but there will be some programing to do.
It doesn't work well. I put MRC sound decoders in a couple of Kato SD70mac's with the idea of one sound equipped unit in a consist. The sound units don't move until the engine revs up to speed, you'd have to adjust the speed tables of all your non sound units as MRC decoders don't have speed tables. I just run the two sound units on their own, the sounds are ok though. I'm waiting to hear more about the F3 decoders, both previous drop in sound decoders only had sound files for either an SD45 or MP15, neither of which they are advertised for! MRC are on the right track and have shown what is possible, but we need someone to do it right, are you listening Soundtraxx, Loksound or Digitrax.
