After repairing the double slip in the yard, I finished reconfiguring my power districts and made a few minor (I thought)  changes to the Loconet plumbing. Ha! When I powered things up, not so good. All of my occupancy zones reported occupied... ooops. Shorting the track in various places made the PM42s trip -- so that was ok. Started checking things -- assumption always is that a new cable was bad... well, I had made a few new cables and changed a couple of existing ones. Got out the little tester and saw right away that railsych was missing on both branches of my network. To make a long story short -- on one side I had moved an SRC16 board I was using for routes triggered by contacts on a lever frame, and on the other side I had added a Loconet Fast clock display. Topologically they were both close to the LNRP I was using to split off the network. My little loconet tester got a lot of workout but what saved the day was an ethernet extension splce (2 RJ45 sockets wired back to back) -- works with the RJ12 plugs and allowed me to drop a board out of the network. Turned out BOTH new items had issues -- they worked but did not propagate Railsych through (and didn't use it themselves). Mutter, mutter.  First time I had my nose rubbed into the possibility that the vendor connectors could be a problem. Make up a few more cables... now those two units are at the end of my loconet chain. And everything is working nicely. What a surprise... it wasn't me.