DIYAPASON-L Digest #400 - Friday, September 28, 2001
 
Wiring :)
  by <Mpmollerorgan@aol.com>
RE: [Residence Organs]  Wiring :)
  by "Gregory Rister" <grandcornet@earthlink.net>
 

(back) Subject: Wiring :) From: <Mpmollerorgan@aol.com> Date: Fri, 28 Sep 2001 22:22:25 EDT   While this was a church organ, the mystery can affect us at home too!   I was sent to a church today to look at a Verlinden organ whose E29 on the =   swell was "stuck" but it was only the St Diapason that had the problem. I spent about 2 hours and couldn't find the problem, it was intermittant = and would cypher the E once every maybe 15 or 20 times played. The key contacts were not sticking broken or making contact with anything = I could see, goin gto the chamber I find the magnet and it's fully = energized, pulled out the armature it was clean, nothing stuck. The ranks I looked at had a magnet for each pipe.   Somehow the magnet was being energized periodically but the key contacts = were not doing it except when the key was depressed. I wound up dropping the key contact rail to look at that contact block thinking maybe one of the 5 wires in the grooves of it wore through the = thin wall between it and the next wire and was making periodic contact with the =   wire next to it. I couldn't see and didn't want to further tear into that. = I did note one of the out leads to it seemed a little close to the other = wires and there was dust on top so I bent that wire over slightly away thinking =   maybe the dust or lint was acting as an intermittant ground.   After that I was unable to get the problem to reproduce, but still felt = that wasn't where the problem was, still I couldn't get the problem back but it =   sure would have been nice to find a specific problem like a broken wire = and know putting in a new one fixed it for sure.           Randall http://members.aol.com/mpmollerorgan/  
(back) Subject: RE: [Residence Organs] Wiring :) From: "Gregory Rister" <grandcornet@earthlink.net> Date: Fri, 28 Sep 2001 19:57:37 -0700   Randall wrote:   > I did note one of the out leads to it seemed a little close to the other wires > and there was dust on top so I bent that wire over slightly away thinking > maybe the dust or lint was acting as an intermittant ground.   Randall, you may actually have found the source of the problem. I had a similar experience with multiple "cyphers" on an organ some months ago, = and none of the usual suspects really panned out as the source of the problem. =   I checked out the underkey contacts with a mirror, and found them full of "dust-bunnies" and unidentifiable debris. Sort of like what you find = under a pedalboard, but in miniature. I blasted out both contact rails with one of those dandy aerosol cans for cleaning computer keyboards (next best thing to a compressor), and the problem disappeared.   And, thinking about it, I've come to the conclusion that any circuit = boards that need to be mounted horizontally in a console should be provided with some form of dust protection. They might not get very dusty in a month, but in five years, ten years or more, they can get absolutely clogged with fine dust. If that dust is of such a composition that it can absorb moisture, you may find that you start getting very weird intermittent behavior from your solid-state components because the dust has become conductive. A nice tight cover will do much to keep them tidy.   Greg Rister The Pipe Organ Craftsmen Pomona, California   > DIYAPASON-L: a Discussion list for owners and builders of their own > Residence Pipe Organs. > HOMEPAGE : http://www.diyapason.pipechat.org > List: mailto:DIYAPASON-L@pipechat.org > Administration: mailto:owner-DIYAPASON@pipechat.org       --- Gregory Rister --- grandcornet@earthlink.net --- EarthLink: The #1 provider of the Real Internet.