Electronics Forum | Thu Jul 11 06:56:30 EDT 2002 | davef
We have had failure due to a leakage in one ceramic chip capacitor. External inspection did not show any obvious damage. Cross section showed a void in the capacitor. The void was an elliptical shape and positioned longitudinal to the length of the c
Electronics Forum | Wed Jul 10 04:53:47 EDT 2002 | redmary
a leakage exists in the capacitor net (1206), which cause the voltage down so much. the process flow is: printing-placement-reflow-hand load-wave-depanel-FT. I find possible stress maybe exists in the depanel stage, does the extra stress cause the ca
Electronics Forum | Fri Jul 12 08:26:51 EDT 2002 | davef
We sent the sectioned capacitor to our supplier for analysis. So, the results of their analysis is probably in a file drawer someplace.
Electronics Forum | Wed Jul 10 22:32:46 EDT 2002 | redmary
i just find the gap inside the component from the cross-section, it indeed exists the interal crack, not solder joint crack. but why the failed capacitor is well after some time. and the other suspicion is the quality of the component.
Electronics Forum | Fri Jul 12 01:38:06 EDT 2002 | redmary
thanks, Dave. who are specialized in mechnical stress distribution? because I find the gap in the capacitor, but why? If the crack is caused by the exteral mechnical stress, which shape will be formed, zigzag or linear?
Electronics Forum | Wed Jul 10 18:19:42 EDT 2002 | davef
Flex cracking under the terminations is generally regarded as one of the primary causes of failure of ceramic chips. If you can see cracks in the solder joints from board flex, those chips are certainly strongly suspect, and you must assume there is
Electronics Forum | Tue Jul 20 08:12:13 EDT 1999 | jacqueline coia
Could someone please tell me if it is possible that erroneous 'leakage current' readings in an instrument could be inheritated by the type, design and fabrication of the PCB itself, if so then where could I find information relating to this subject.
Electronics Forum | Thu May 08 18:12:42 EDT 2008 | russ
Thanks Wolfman! Russ
Electronics Forum | Thu May 08 10:06:21 EDT 2008 | russ
Does anyone know of where/who to get test equipment to verify Xray cabinet is not leaking? Thanks in advance Russ
Electronics Forum | Thu May 08 18:02:29 EDT 2008 | jwolvans
Russ, Take a look here: http://www.geigercounters.com/Monitor4.htm You can buy one already assembled, or buy the kit and build it yourself. I've built two of these kits, they work just fine.
