I've experienced the same problem too once in a while, in a mass produced unit. Sometimes a 1uF/50V 1210 SMD ceramic cap fails resulting in an almost short. This cap is charged from a car battery via a 6800 Ohm or 16kOhm resistor. Perhaps 1uF/50V in a 1210 shape is pushing capacitor technology resulting in weaker parts. Anyway, I won't place this cap type in newer designs anymore. Smaller values don't fail. Daniel... ----- Original Message ----- From: David Duffy To: Sent: Friday, April 27, 2001 08:11 Subject: Re: [PIC]: Pin impedance SOLVED > At 12:51 AM 27/04/01 -0500, you wrote: > >At 03:31 PM 4/27/01 +1000, David Duffy wrote: > >>At 11:57 PM 26/04/01 -0500, you wrote: > >>>Turns out, it was a 0.1uF leaded monolithic cap, that had developed an > >>>internal "short" of 11.2k. > >>> > >>>I've seen them fail shorted (near zero R) before, and open, but never 10k! > >>> > >>>It's a more complicated failure though, as I wasn't able to pull it up to > >>>5V, even with a 1k resistor. > >>>47 ohms got it there though. Sort of like a bad zener, and definitely not > >>>what you expect from a capacitor! > >>> > >>>FWIW, there's the culprit. > >> > >>I always use MKT's for audio and timing applications. The mono's seem > >>to curl up and die when used for other than PSU de-coupling purposes. > >>Maybe it shouldn't be so, but repair experience has shown it to be true. > >>Regards... > > > >All this one had to do was get charged and discharged through 10k and > >10-150k resistors to 5V. > >Hardly a stressful app.. > > All I can say is that's exactly how I've seen them fail. :-) > Can't explain it - it just happens!! > Regards... > > -- > http://www.piclist.com hint: PICList Posts must start with ONE topic: > [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads > > -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads