RAILforum: selector trouble

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Posted by woodguy (Member # 2319) on :

I am having some weird trouble with my layout wiring. I have two MRC power packs - 1 of which is about 15 years old and gave out on me a few months ago. I have since discovered that MRC's supposed 5 year warranty can extend indefinately in some cases. My Railpower 1400 had a blown power transistor, which was diagnosed, repaired, and returned to me at no charge. You couldn't ask for any better service than this!
Anyway, back to the problem. Before I hook the unit up to the control panel again, I decided to test the circuits. I am using Atlas selectors, and the new pack is in position "B", the old (repaired) one in "A". With B at full power and the selectors in position B, I am getting 22.68 V. However, with the selectors off or at A, I am getting some stray voltage on the output side of the selectors. Some of the 12 switches get 0 V as they should, but some are getting up to 3.36 V. Is there maybe something wrong with the selectors? Does anyone know of any such problems with these, or have any suggestions? I would like to figure this out before I connect my repaired unit to the system.

Thanks in advance,
Woodguy

Posted by Shaun CN (Member # 2366) on :

Soory I have not had this problem before. I am ussing atlas selectors from 30+ years ago and they are working fine. Maby you should try wireing the repaired powerpack up to the selectors and see what happens. Soory I could not be of more assistance. Maby you should purchase another selector. Theye are not that expensisve.

Shaun CN

Happy modeling!!!!!!!!!!!!!!!

Posted by Challenger (Member # 1298) on :

Hello,

I have a guess as to what could be wrong with your selectors.

According to "The Complete Atlas Wiring Book" their selectors are "four single pole double throw "SPDP" sliding buttons which determin current routing"

Having seen one apart I know that each slider has alot of metal around in a pc board trace like fashion so as to properly connect the power. However it is not out of the relm of possibility that that some of the metal is overhanging where it shouldn't and thus allowing the small amount of current bleed through.

One question I have to ask is. Is the bleed through effect the same for a whole box. In other words are all four terminals in the same box reading the same amount of bleed through or is it different for each terminal. If it is the former. I would consider them defective and replace them. I would go to you hobby shop and explain them your problem and see if they would not be willing to replace them or at least let you test them before purchasing them.

If it is the second. I would talk to others in your area and see if this is a common problem.

I also remember reading someplace that Atlas had a warranty on thier products. But alas I cannot find it and verify that is true. You can possibly call them up and see if they have had this problem before. Their phone number is 908-687-0880. If they have not, I would ask if they would like a sample of one that has so they may be able to determin cause and possibly make modifications to correct it and thus improve the line. They may offer to swap if you make this offer.

This is all the advice I have for now. If I think of anything else I will be sure to add it in.

James

[This message has been edited by Challenger (edited 07-18-2003).]