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Wacky computer problem - HELP!! 1800

Greg;

I have just started following this thread...Please confirm: The computer is hick-upping (probably reseting, or acting as if power has been momentarilly cycled) upon dropping power to any onboard relay...

If this is the case, it suggests that the spark created by the collaping mag field is affecting the FI computer in a nontypical way. Your FI comp MAY, for some reason (like a dried out electrolytic capacitor internally), be more suseptable to this type of spike...I propose a couple of tests to confirm this suseptability, and if you confirm this will have a couple of of solutions to propose.

Tests to try:

1. Using an oscilloscope if available, measure the magnitude of the (neg) voltage spike across the FI comp power connector (RIGHT AT the power connector) at relay turn-off.

If no scope is available, try connecting a "free-whelling diode" (type 1N4002, better yet, 1N5402) reverse polarized, across one relay coil to suppress the spike...does computer still hick-up? Try connecting clamping diode RIGHT at computer power input...repeat test. Try diodes at BOTH locations....repeat test. Try connecting an 1000uF 100V electrolytic capacitor (correctly polarized across the power terminals of the FI comp, RIGHT at the FI comp, (to do the filtering work of a nonfunctioning internal one)....repeat test.

Please advise results. Good Hunting!







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New Wacky computer problem - HELP!! [1800]
posted by  carnut222  on Fri Nov 28 15:36 CST 2003 >


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