I read this, which is excellent work.
1. I removed all devices connected to the Avionics switch (lit with an LED > indicator) which is the culprit. > 2. I disconnected the wire supplying power to that switch (the switch > status is off) from the power buss. > 3. Then turned the switch on > 4. I touched the wire from the switch to the buss bar > 5. I observed an arc, and the wire became hot (as in heat). > 6. No breakers tripped though it was connected to a 5A breaker > 7. When I removed the wire from the buss, again a small arc followed. > 8. While the switch was on, I observed the battery drain from a normal 12+ > Volts to as low as 10.5V > 9. I removed the switch and replaced with a common toggle switch (rated at > 10A) > 10. I reconnected the circuit to the buss, and I did not observe arching > nor did the wires get hot. > The only additional tasks one of my techs would perform is to take test equipment to the removed part and find it's new set of electrical characteristics and compare those with the previous data, ensuring the fault in the part is certified to satisfy the conditions of the earlier observations. With that done a decision is made whether time and conditions allow to disassemble the part and find the actual failure mode. It conditions permit, we would do that. We did not do that for the customer but instead to cause us to know more about that switch in the real world than the guys who built it did. We knew things, lots of things, and we were always looking for more. BTW, Did I mention that was excellent work? cheers! jg >
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