Well, here goes. First attempt at blogging. After reading the interesting going's on of our many talented members I thought I'd take the plunge. Not sure it will be worth reading but I think my grandson's will get a kick out of it. Their dad's will have to read it to them as they're still to young to read. They love to run "Bapa's" train and since I upgraded my Prodigy Express with the Advance cab I have 2 cabs. One for them, and one for me.
Todd or Bryan said that this is a good place to describe new projects or progress on current ones so here are a couple of recent projects.
Two things bugged me about the Prodigy system. One was the long, 8 conductor, flat ribbon cable that connects the cab to the base unit. It seems to always be in the way or getting run over by my rolling office chair that I use when running the trains. The Tech guy at MRC, Frank( rrtech@modelrectifier.com ), is very helpful and readily shares technical information. Originally I thought I might be able to use a 4 conductor cable from an old phone handset, but Frank said "that all 8 conductors are used, but they are doubled up so there are actually four. They go from outer to inner as this...
4-3-2-1-1-2-3-4
both 4's are the same
both 3's are the same
both 2's are the same
both 1's are the same"
He also stated that "you might get a volt drop through the throttle bus if you use only 4 conductors that is why they were doubled, [also so if the locking tab breaks off and someone plugs the cable in upside down there is no harm to the system]."
I found a source on the net http://specialtywire.com/ that sells retractable cable at a reasonable price. As I recall they were about $12 plus shipping. I added 2 RJ-45 plugs to the ends and, viola, very neat and compact as the picture below shows. ( As I said, this is my first attempt at a blog and using Live Writer. We'll see if the pictures move with this draft.) The RJ-45's require the use of a special crimping tool that isn't cheap but the computer geek next door or down the street should be able to help you out.
My second issue with the Prodigy is a little more technical but with a few spare parts I was able to solve an annoying problem. I'm not sure how other DCC systems handle shorts but the Prodigy flashes the dreaded SVdA on the display screen whenever there is a short and, apparently, the only way to clear it is to unplug and re-plug the RJ-45 from the cab or power down the entire system. While in the SVdA mode the trains continue to run so time is of the essence when you need to regain control. Not only is unplugging and plugging in the RJ-45 a pain in the backside, it's impossible for 4 and 5 year olds. It also puts a lot of wear and tear on the plugs and cables. Perhaps there is a better way to solve the problem and if you have one please let me know but here's what I did:
I had a couple of Radio Shack DPDT 12 volt relays in the spare parts bin and that got me to thinking that if I got 2 more I could have an 8 conductor switch that would break the circuit without having to do the plug /unplug thing. I put the four relays together, soldered the cat5 cables to the to the normally closed terminals, carefully matching each color strand to the opposing pole, then connected the 4 relays to a 12 volt wall wart with a momentary contact push button switch in the line. When you push the button, the relays opens the circuit. Hold the button for 2 or 3 seconds, release it, and you are back in business. Here are a couple pics of the finished project.
There was a thread recently http://www.nscale.net/fal8bw/2007/08/27/relays-memory that lists a great site for relays. Thanks to Joe for the link. I think if I were going to do this again there are some smaller and better relays for the job. The ones Joe is talking about are latching relays but they have normally closed DPDT as well as 4PDT that would work for my application.
That's about it for now. If anyone reading this has another way to solve the SVdA problem I'd love to compare notes.
Bapa John
