the biggest culprit when it comes to older electronics is the good old
tantalum cap. I have seen these be a little resistive, dead shorts, etc.
good luck.
best regards, Steve Thatcher
At 08:21 AM 12/01/2004, you wrote:
>I've got a board here with a short between ground and the +5V rail
>(actually not quite dead - I'm getting around 10 ohms between the rails)
>
>Any useful tips for finding the fault? It's a large board, multi-layer,
>lots of silicon on it unfortunately :-(
>
>Are there any particular components that are likely to fail in this way
>that might be found across PSU rails? (decoupling caps, certain ICs,
>crystal modules etc.?)
>
>Given a suitably sensitive meter is it sensible to assume I can try and
>home in on the short location a little? (I've found readings between
>GND/supply on various LS chips of anything between 9.5 and 12 ohms so
>far)
>
>I've checked the board for particles of anything that might be causing
>the problem, plus I'm halfway through ruling out any of the socketed
>ICs. Of course if it's a problem with the multi-layer PCB itself... eek!
>(do these ever fail in such a way though? It's a commercial board which
>used to be fine)
>
>cheers
>
>Jules
Received on Wed Dec 01 2004 - 16:08:36 GMT
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