The rule at my last job was you could choose to call immidiately or you could choose to tinker with the problem, but you must call tech support after an hour of working at the problem, or at least call the boss and ask if he or any other tech knew the answer. We did a lot of "system rehab" (ie take over a semifunctional, disfunctional, or nonfunctional alarm, camera system, telephone system, or whatever that a previous trunkslammer had thrown up their hands and given up on), which meant hours and hours of troubleshooting. In cases like this, where there is no tech support to call, we'd tinker for an hour and call or text the boss with a status report. The status report had to include actions taken ("I toned out a quarter, half, all the wires in wiring cabinet 1B"), tasks accomplished ("I identified, labeled, and verified the connections on 1, 5, 100 wires"), issues holding up work ("cannot identify wire 137, am unsure if the wire is broken or the jack is on another floor and they just ran it to this closet for some reason") and intentions ("will try tracing wire to see if I can find the break, or figure out if it's running in a different direction, or what", or "tried changing the baud rate on the PTZ, no result, verified connections as good, am calling Pelco now") At every break, and at the end of every day, we had to send an additional status report recording all that we'd done from the begining of the workday, and what our next step was going to be, after lunch or the next day.
It's a good system, I think. First, the boss knows what the tech is up to, what the tech already tried, and can either offer their own insight into the problem or at least have a good idea of how much longer troubleshooting is likely to be. Second, forcing the tech to stop, think about what they've tried so far, and think about what their next step should be often leads to insights that wouldn't be forthcoming if the tech gets to tunnel-visiony (a problem I find myself particularly prone to).
So. An hour of tinkering, not more, but more important than the time limit is to stop, gather your thoughts, think about what you've done so far and why, and what you think should be happening or what you want tech support to do for you ("tell me how to adjust this particular setting so that it doesn't interfere with that particular setting" is more useful than "get this razzle-frazzle thing working for me, you stupid jerk").