All, Speaking of replacing electrolytic capacitors, which I am now doing on a Fluke 845A, I found a carbon comp resistor way out of spec. It is a 150 ohm, 1/4 watt current limiter, for a 10 Vdc zener. I noticed that it had looked to have been hot (or gave off excessive heat), and had made a shiny place on the PC board above it, though the resistor doesn't show any burnt color. When I measured it, it was reading around 1 to 2 ohms. The zener was still good, luckily, as was the bridge rectifiers, and filter cap (though bulged), and this is the supply voltage for the switching transistors, which run the chopper transformer.
My question is, have any of you seen a 150 ohm carbon comp resistor change that much in value? I wouldn't think they could, but evidently, this one did, and if so, I wonder about the others in the meter. Thanks, Will *********** REPLY SEPARATOR *********** On 6/24/2011 at 11:22 AM Brooke Clarke wrote: >Hi Chad: > >Google found it: >http://techdoc.kvindesland.no/radio/passivecomp/20061223155312558.pdf >But it's not that informative. > >The best info I've seen on measuring components is the HP (Agilent) >Impedance Handbook. >http://cp.literature.agilent.com/litweb/pdf/5950-3000.pdf > >I measured dozens of caps using a number of different methods to see how >well the combined ESR and Capacitance meter I sell works. >http://www.prc68.com/I/ESRmicro.shtml >http://www.prc68.com/I/Capacitors.shtml > >Does anyone know of a modern cap leakage tester? > >Have Fun, > >Brooke Clarke >http://www.PRC68.com > > >GMail / AnalogAficionado wrote: >> Cyril Bateman called Understanding Capacitors > >_______________________________________________ >time-nuts mailing list -- time-nuts@febo.com >To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >and follow the instructions there. > >__________ Information from ESET Smart Security, version of virus signature database 5851 (20110206) __________ > >The message was checked by ESET Smart Security. > >http://www.eset.com _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.