Troubleshooting:
10 common issues

A rule that works, and the reasoning behind each part:

• Twenty minutes on the obvious things. Input, power, network, restart. These four cover the large majority and none of them requires understanding anything.
• Then swap, don't investigate. A replacement player costs less than an hour of anyone's time in almost any business. Swapping it also tells you the answer for free: if the new one works, it was the old one; if it doesn't, you have eliminated the device entirely and know to look elsewhere.
• Investigate later, if at all. With the screen working again there is no urgency, and most of the time the answer stops mattering. The cases worth understanding are the ones that repeat.

This inverts what feels responsible, and the inversion is the point: the expensive resource here is attention, not hardware. A twenty-euro device treated as something to be repaired consumes far more value than it cost, and the person doing the repairing is usually the one who should be serving customers.

The rule only works if the swap is actually possible, which is a decision made months earlier: a second device, configured, in a drawer. Without it, «swap» means ordering something and waiting, and the whole logic collapses back into investigating because there is nothing else to do.

One exception worth naming, because it is the case where investigating first is right: if the same fault has happened before. A repeat is not a fault, it is a pattern — bad power, a network that drops nightly, a device overheating in the same spot. Swapping a device into a bad location produces a second failure a few weeks later, and that is the situation where twenty minutes of thinking genuinely pays.

Write the date on a note every time something goes wrong, even briefly. It takes five seconds and it is the only way to tell a one-off from a pattern — which is the single distinction that decides whether to swap or to think.

The screen is the least important thing on that network and it is the one being fixed. A restart of the router or the switch also restarts the payment terminal, the booking tablet, the kitchen printer and whatever the office is uploading. None of that is obvious while you are standing on a chair looking at a black rectangle, which is exactly why it happens during service. The rule that avoids it is one line long and worth agreeing before anything breaks: nothing shared gets restarted while customers are in.

What that leaves for the busy hours is a shorter list, and it is enough more often than you would think. Restart the player alone — its own plug, not the strip it shares. Check the physical input on the screen. Look at whether the content is stale rather than absent, which is a different fault and never urgent. If none of those work, the screen shows the wrong thing for four more hours, and four hours of the wrong thing costs less than three minutes of no card payments.

And there is a version of this that catches people out at the other end of the day: the fix applied at closing time that is never verified, because everyone leaves. If you restart something at seven, the thing to check is not that it came back — it is that it comes back tomorrow morning on its own, which is a different question and the one that actually decides whether the fault is over.

It looks identical to a real fault from the outside, which is why it wastes so much time. The screen is on, the content is wrong, nothing shows an error — the same symptoms as a failed sync or an expired schedule. The difference is that no amount of restarting will fix it, and an hour can go into the device before anybody thinks to ask a person. So the first question is not technical: who has been in the app since it was last right, and what did they change. In a business with two or three people, that question ends the call more often than any reboot.

The fix is not access control, it is a habit that costs one line. Whoever changes something says so where the others will see it — the group chat, the notebook by the till, anywhere shared. Not for accountability: so that the next person who notices something odd starts from « ah, that was Marta on Thursday » rather than from the assumption that the system is broken.

And it is worth naming the version of this that catches everyone eventually: the change made on a phone, in a hurry, that went to the wrong screen. Two devices in one account and similar names are all it takes. If that has happened once, rename the screens after the wall they are on — « window », « counter », « back room » — and it stops happening, which is a cheaper fix than it sounds.