Reply to post: I tend to listen to the customer first

I tend to listen to the customer first

I've had some odd and, at first glance, seemingly improbable faults come my way over the years - from the individual connected to a cross-bar exchange who complained that the first call they made each day would fail to connect*, to an optical add/drop multiplexer that would undergo an autonomous reboot of its controller card every six weeks, +/- a couple of days.**

It's always worth giving the customer a hearing - they know more about what they think is wrong than you do at the start.

* Grease on the flat select bar restore springs was causing the select bar to stick slightly, preventing their line from being selected and connected to a register within the timing limits, so they got disconnect tone rather than dial tone. Once the spring had been unstuck by the first call attempt it worked fine all day.

** A reference clock extraction and selection circuit in a card unrelated to the equipment controller was, in some way which I still don't fully understand, interfering with the controller card operation and causing the well timed reboots.