Friday, April 24, 2009

Short solved -- and more

I previously mentioned that there was an electrical short somewhere that affected the middle and lower tiers. I'd spent probably an hour or so trying to find it with no luck, so I stopped looking on March 28th and focused on the upper tier.

Today, with the middle tier ready for new track, I started the search afresh and found it within a few minutes. The guilty bugger was the staple on the left shown in this picture:


As often is the case, when you set a problem aside then revisit it later you find a new approach that works. In this case I realized that, having looked at everything 3 or 4 times, the problem almost had to be a staple that penetrated the insulation on both wires. Then I realized I could find it easily by using the multi-meter and checking for resistance between each staple and the track. Sure enough, this one registered loud and clear on the meter, and the repair took a minute.

Once that was done I started putting down new track. This picture shows the glue drying on two new track sections:


A close look on the left side of the picture reveals that there is a second layer of the blue roadbed on top of the first. As I noted in my last construction post, the new plywood I'm using is about 1/8" thinner than the old, and this caused the transition from one to the other to be uneven, even after I shimmed it. The second layer of roadbed seems like it causes no problems, however in order to keep the track as smooth as possible I'm letting this dry in place, without weights on it. This is an experiment -- if it works I might use the same technique for the rest of the staging track.

Next up: lots more track installation on the middle tier.

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