I have two CM 20's on the layout, one with the fan and one without, with walkaround throttles and phone jacks spread through the layout. The one without the fan performs near-flawlessly, while the one with the fan has been problematic, either being unable to reverse direction, or a runaway train occurs. This was traced to the phone jack connections; if you wiggle it the momentum light flickers, or push it in hard and it will work fine...for a little while. I've tried different, new jacks and cords, with not much luck. The unit without the fan is wired identically with the same jacks, and is rarely a problem. Has anyone had problems with the connectivity of the jacks? BTW, MRC tells me today that they are no longer repairing these CM 20 units. John
The throttle is connected to the jacks spread throughout the layout, not directly to the CM itself. The connection at the CM does not move at all. Thanks!
is it possible that it is the plug on the hand held having a pin that doesn't quite line up or maybe is miscrimped? (not sure if they are interchangable, i don't have one of these).
Spoke with Doug at MRC; he said we're supposed to be using RJ12 jacks, not RJ11. Not exactly sure which one I used; will check when we get back in town. At any rate, maybe all I really need to do (since it worked fine before) is to (somehow) carefully pull out the wire pins for better contact? He also confirmed they're no longer servicing the CM20's.
i would check the plugin piece on the end of the cord that plugs into the socket and check that the plug is not mangled. Also check the socket to make sure the wires are not crushed down. If pushing the plug into the socket further works that could mean that the wires in the socket are crushed. You may be able to use needlenose pliers to straighten the pins but it may be faster to replace the sockets or the plug.
RJ12 is 6 pins, 6 conductors. RJ11's are 6 pins, 4 conductor. The size of both is the same. You want ones that are marked 6P,6C. Both types have 6 slots. Jacks wired for RJ12 standard will have 6 wires using all 6 contacts. Care should be taken to match the color arrangement of the old plug when replacing with new. if it doesn't work, cut it off and try a new one because they cannot be easily repaired. 6P,6C plugs can also be used for RJ11 by leaving the two outside contacts vacant and using only the center 4 contacts. Martin Myers
I think I got it figured out: My Cab B jacks are installed upside down, so not to accidentally plug them into the Cab A jacks. And the Cab B jacks are the ONLY ones we have problems with. Cab A jacks are installed right-side up and are rarely a problem. So I was thinking maybe it's the upside-down installation that is causing problems, maybe putting undesired pressure on the pins causing them to deform, or maybe pulling the internal contacts away from the pins making for unreliable connections. The weight of the 15' coiled cord pulls down on this jack. I'm thinking the solution to this would be to find another 4-pin connector with a wall mount, such as an XLR4 jack. It'll be sturdier, too. Thoughts? John
constant pressure on the pins due to the weight pulling down on the plug very likely is going to cause deformation of the socket. I would recommend as you suggest as well, a different socket. If it is 4pin, wouldn't an inexpensive RJ11 socket work as a quick test?
John, Having some knowledge of the layout I think you are on track with trying another style of plug. Never mind the soldering and fuss to make it work. Since visitors to your layout have operated trains using the CM20 Cab B., anything is possible and deformation of the plug is highly likely. I operated with Cab A last Wednesday and had little to no problems with it. Avoiding stretching and pulling on the cable...helps! Have a happy 4th of July and may those aliens stay away yet another year.
