I have converted my MMI K-28 to DCC, but am having trouble find engine to tender cables flexible enough
to prevent binding. I prefer installing my Soundtraxx decoder in the tender instead of the engine since it is
easier to access when you need to. I am using miniatronics micro mini connectors which are too stiff. Any ideas where I can find what I need?
John,
I guess you’re in On3 or On30? The wires will be short so probably still heavy enough to carry the current even if very small gauge. In HOn3, I use the wires that come with your old fashioned computer mice. They’re cheap and easy to find, because it doesn’t matter whether the mouse works.
One trick to keep in mind is to X the wires. In other words, the half of the wires to the right side of the loco should crossover to the left side of the tender and vice versa. This helps even out the sideforces when on curved track.
Being a DC guy, I’m not sure how many wires you’ll need between the loco and tender, but I’m guessing that it’s at least four. Part of the problem may be that the wires are cabled together rather than separate, making the cable much stiffer than would be the individual wires. Would it be possible to use individual wires, soldered to a bar of connectors like the uncut one shown below?
I’d install the female connector bar on the tender, either within the front of the coal bunker or below the floor, with individual wires from the rear of the loco terminating in a suitable multi-prong male connector. If there are only four wires involved, you may wish to pair them, and use separate double connectors on each side.
Here’s a DC installation on a brass steamer, which I modified to have all-wheel pick-up:
Compounding your problem is the fact that your loco is narrow gauge, with less room available within both the loco and tender for extra weight. If there’s room available, adding weight will improve tracking and lessen the possibility of the stiff connection causing derailments. It also improves electrical conductivity, and more than compensates for any minor decrease in pulling ability. If you add weight to the locomotive, be sure that it’s balanced about the centre-point of the driver wheelbase, as this has a direct bearing on pulling power.
I got the mini-connectors at Sayal Electronics, but any ware
I have not coverted any of my MMI models, but I will consider using wires one each side that hang down simulating the water connection to the locomotive. This way the wires will flex without causing any problems with very little binding since they loop down. I normally use wire for Phonograph arms. I am not sure if this wire is available any longer but Fry’s or any major electronics supplier should have some wire that is close to what I use.
The connections from the tender should be pointed down to simulate the water connections and the same can be done the loco.
CZ
I neglected to mention the very flexible wire which I use, but it’s from Brawa, their part number 3168. It should be sufficient for the draw of most motors, as it easily handles 2 amps for the older open frame motors.
Wayne
Thanks Wayne. This loco is On30 and weighs about 7 lbs. So the stress is really on the wires. I am using 2 mini connectors with a pair of wires each. After running a while, the connectors come loose because the wires
are so stiff. Being a senior, my soldering skills are not what they were, so I am trying to find something
already made up.
John
I should have guessed about the scale [banghead] - wish my HO locos were of a comparable weight, but the best I’ve been able to do with my plastic standard-gauge Mikados is about 1.5lbs., tender included.
While it would still require soldering, miniature phono-type jacks would do the job, and properly positioned, the wires would do a decent job of representing the water connections between the loco and tender. They’d also be a lot less likely to disconnect themselves.
Wayne
That’s an idea, I’ll look into that.