gene heskett wrote: > > > I believe that may be the maximum self destruction voltage, assuming > sufficient is available to reach that. At my dvm's diode range, I checked > 6 of them, 3 had never seen power, and they all read a couple of millivolts > from .989 volts forward, and with nearly 21 ma now flowing its just a few > millivolts above 1.24 volts. > > OHHHH! These are IR LEDs, which have a lower forward voltage than visible light LEDs. Those voltages sound right to me. > > Working from one of those 8 ounce bags of 5 or 10 each tape bound 1/4th > watt R's the shack has peddled for years, I spotted the 150's thru the bag, > but when my hand came back out of the bag, it had 150k's in it, third strip > a pale yellow. So, swapping them out, and they actually read 147.7 ohms > this time, I now have 3.098 volts across the resistor in series with each > LED, and the led voltage is showing at about 1.24volts for all 3 of them. > So now I have 3.098/147.7= 0.0209 amps thru each one, and they switch as > expected when the slot is blocked. > > Ah, that makes complete sense. > These 1 oz circuit boards aren't really made tuff enough to be repaired, so > there is now 3 pieces of wire wrap bypassing broken traces >
> TBT, I really need an iron with about a 1/10th sized tip & only maybe 10 > watts for this, Yes, a good iron is a KEY tool! You should see the stuff I do manually. 0805 passives and chips down to 0.4mm lead pitch. I do a lot of work with a stereo zoom microscope. I use Weller EC2002 controls and the Weller EC1302B iron, although these are getting pretty hard to find on eBay. Repair parts are expensive. The WSL box and WMP iron are almost as good, but insanely expensive new. Jon ------------------------------------------------------------------------------ Keep Your Developer Skills Current with LearnDevNow! The most comprehensive online learning library for Microsoft developers is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3, Metro Style Apps, more. Free future releases when you subscribe now! http://p.sf.net/sfu/learndevnow-d2d _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
