DIYAPASON-L Digest #852 - Saturday, August 2, 2003
Just when I thought I had it all figured out....
  by "Paul Soulek" <>
Re: [Residence Organs]  Just when I thought I had it all figured  out....
  by "Larry Chace" <>

(back) Subject: Just when I thought I had it all figured out.... From: "Paul Soulek" <> Date: Sat, 2 Aug 2003 16:06:32 -0700 (PDT)   You may remember my problem with my Rodgers pipe control system---each time the organ turned on and power is applied to the driver boards, one of the pipe driver chips pops and smokes (it doesn't matter which one...each time it's a different one). Two local electronics techs. isolated the problem down to "hex Schmitt trigger" (a "4106") that interprets and distributes the Clock-Strobe-Data information. We replaced the "hex Schmitt trigger" on our chests with parts from the local Rodgers tech (local means a 140 mile drive yesterday....) , but we still have the same problem. (this is the gedackt chest)   Now we are having problems with the principal chest also. When the organ is turned on, all of the pipes go on at once. We unplugged the clock-strobe-data to the driver board so that just the power was hooked up. Same thing happened---all of the magnets opened. Our electronics techs. tell us that this was a problem with the hex Schmitt trigger too---but replacing it does no good.   One useful piece of information on both of these items could be the voltage---the system is supposed to use 15 volts, but when tested, it shows around 19.2 volts. Could this have "burned out" the "hex Schmitt trigger" so that strange things happen? (driver chips blowing up, grand cyphers...)   I'm lost (and somewhat disappointed). Any help that any of you could provide would mean the world to me.   Thank you!!!!!! Paul     __________________________________ Do you Yahoo!? Yahoo! SiteBuilder - Free, easy-to-use web site design software  
(back) Subject: Re: [Residence Organs] Just when I thought I had it all figured out.... From: "Larry Chace" <> Date: Sat, 2 Aug 2003 22:41:40 -0400   Paul Soulek described a problem. The chip in question is probably a "40106", also known as "4584 or 74C14", which is in fact 6 Schmitt trigger inverters. The 4000-series of CMOS integrated circuits is specified to operate on voltages up to about 18v. A supply voltage of 19.2v is just beyond the specified maximum. I'd say that the "15v" supply is probably one of those (in)famous wall-warts that puts out more than its stated voltage.   (Maybe I'm wrong, but 19.2v is really too much for the poor little CMOS guys, who will operate very happily on, say, 12v or 15v for years at a time.)   Replacements are available (via the web) from many sources, including, but not limited to :   Expect to pay about $0.50 each, or maybe less.   From Paul's description, it may well seem that there is something else wrong, but I'd correct the voltage supply first. The good folks at Rodgers should be able to provide good advice.   Larry Chace