On Monday, December 26, 2011 10:43:05 AM Igor Chudov did opine: > I had, recently, a couple of instances of electronics failing, > seemingly, from cold weather. > > 1. Netgear GS-108 8 port gigabit switch failed when I left on vacation > and let the house cool to 52 degrees F. > > 2. Saitek USB joystick on my CNC mill failed when the garage cooled to, > perhaps, 40 degrees F.
Electrolytic capacitors being used at a very small fraction of their labeled voltage rating will 'deform' and lose capacitance, and cold weather tends to exacerbate it, often because the pressure held internal connections to the foil fail at the same time. They will generally exhibit a high 'ESR' (Equivalent Series Resistance) prior to that, which if there is enough current to warm the resistance, will exhibit "It has to warm up for 10 minutes before it works right" performance. The heat will tighten the crimp and make a better connection. Either one might also fail because a microscopic crack has formed around the lead of a part. Re-warming all the soldered joints & adding a small amount of fresh rosin cored solder might help in that case. I have one of those saikek game pads but haven't checked it for function in a while, I could not do sufficiently precise work with its teeny little joystick buttons. > I am wondering, what specifically could possibly account for those > failures, what mechanism. Thanks. Those would be the 2 major failure mechanisms. There are others, but stastistically an extremely rare occurrence in my 60+ years of experience. That would make me check the capacitors in the netgear, and the solder joints in the joystick. Also note that 99.99% of the capacitor 'testing' DVM's do not measure this ESR phenomenon, the single most important characteristic of a capacitor. There is a guy, was in Omaha but could have moved, that makes a 'Capacitor Wizard', sells for $175 (when I bought one for the tv station 15 years ago), which does measure this. It measures the resistance of the capacitor with a 100khz test signal of about 80 millivolts. So it can do it in circuit, power off of course, without making a bad cap good again. And with that low a signal level, any semiconductors are out of the circuit. We have a 3 pound coffee can nearly full at the tv station, of teeny little surface mounted bad caps this thing has found, probably saving us $200,000 in replacement PCB boards over the years since I bought it. One place to see & buy it is: < http://www.suburban-electronics.com/display/CAP1B/Capacitor-Wizard> Google will find other places too. Perhaps saving a few dollars. But to put this in perspective, at its cost, the router & game pad can be replaced, with enough left over for a 12 pack. ;) Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) My web page: <http://coyoteden.dyndns-free.com:85/gene> Boy! Eucalyptus! ------------------------------------------------------------------------------ Write once. Port to many. Get the SDK and tools to simplify cross-platform app development. Create new or port existing apps to sell to consumers worldwide. Explore the Intel AppUpSM program developer opportunity. appdeveloper.intel.com/join http://p.sf.net/sfu/intel-appdev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
