this I feel is a typical troubleshooting scenario. many a times lack of understanding of the topology of the circuit , component charactetistics may result in this. for example an opamp based schmitt trigger may appear like a non inverting amplifier ( first impression on circuit topology) and if one has to torubleshoot a problem , lack of understandign of the topolgy may create more errors than a possilble solution.
Rob, it may be more cynically stated that "the customer always lies." Or, at least, "the customer never tells the whole truth." Troubleshooting such problems almost always means you have to be a Missourian: "Show me" or it didn't really happen.
Here's another good example of why it's important to dig down to the real problem. What appears to be the problem at first may not actually be the problem. We're seeing this again and again in the Sherlock Ohms posts.
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