I have a panel AP installed at home, but what should I do if the WiFi in one room suddenly disappears? Don't remove the panel yet, 90% of it is stuck on the AC and that cable.

My new house has an AC+AP set, with one panel AP in each of the four rooms. The AC all-in-one machine is plugged into a weak current box. It has been used for more than two years and has not had any problems. One night last month, I was playing games in my study, and my ping suddenly jumped to more than 300. After two minutes, I was disconnected. The name in the WiFi list was still there, but after a while it prompted "Unable to join the network." I took my phone and went out to take a look. The living room and master bedroom were all fine, but the study became an island.

The first reaction is the same as that of most people: The panel is broken and needs to be removed. After a night of troubleshooting, we found that there was nothing wrong with the panel. The real culprit was a loose network cable in the weak current box. Looking back, the troubleshooting sequence for this fault is actually very fixed. 90% of panel APs "lost connection in a single room" are stuck in the same places. If your home is AC+AP and the WiFi in one room is gone, follow the steps in this article first and don’t remove the panel right away.

Take a minute to figure it out first: Is it because the WiFi is gone or the network port is completely gone?

This step is the most important because it directly determines where you will check later. The method is crude but effective: Take your laptop, find a network cable, and plug it directly into the network port under the panel AP in the study (panel APs usually have one or two LAN ports underneath). If you don’t have a computer at hand, your mobile phone can also do it: Insert a small USB port to the network port and see if you can get the address. The effect is the same.

My test results at that time: When the computer is plugged into the network port on the panel, the local connection shows "unrecognized network" and I can't even get the self-made address 169.254. This shows that the problem is deeper than WiFi - not just the wireless is broken, but the entire wired link to the weak power box in this room is broken. If you plug in the network cable and can access the Internet normally, but the WiFi cannot be found or connected, then the problem is locked in the panel itself or its wireless settings.

By the way, the first mistake I made that night was not to do this step of testing. I just lay on the ground and disassembled the panel. I disassembled and checked the antenna and power supply for a long time, all in vain. Classify first, do it later, this minute can save you an hour. The network port test can also easily eliminate an own goal.: There are no network cables running behind the panels of some old houses, just blank panels. I helped a colleague check "no WiFi in the room" once, and found that it was not an AP at all, but an ordinary network port panel - poor WiFi signal and missing WiFi are two different things. The former should be checked according to the signal dead zone.

Step 2: Log into the AC backend and see if it recognizes this panel.

In the AC+AP architecture, each panel AP is a "subordinate" of the AC. The AC backend can clearly see whether the panel is alive, dead, or offline. Enter the management address of the AC all-in-one machine from the mobile browser (mine is the TL-R47X series of TP-Link, the address is 192.168.1.1 Changed 192.168.2.1 , each one is different (see the sticker on the phone) and find the "AP Management" or "Online AP List" page.

What I saw at that time was: Of the four panels, only three are online in the list. The one in the study room has disappeared from the list and is not even in "offline" status. This basically confirms two things: The panel itself may not be broken (if it is broken, some ACs will keep an offline record), and the path between the AC and the panel may be broken.

If the panel in your AC backend shows "offline" instead of disappearing, don't worry, just touch the temperature of the panel. The panel AP is stuffed in the 86 bottom box, and the heat dissipation is inherently poor. In the summer, when the temperature is so high that it is too hot to touch, there is a precedent for overheating protection to shut down the wireless. The restaurant at my cousin's house is so "bad" that I turned off the air conditioner to cool down for half an hour and I was able to survive. For this kind of heat loss, removing the covering and leaving a gap for heat dissipation is the root cause. The panel AP must not be covered by curtains or bedside tables.

Step 3: Go to the weak current box, 90% of the real culprit is here

The panel AP pulls a network cable from the bottom box back to the weak current box, and plugs it into the AC all-in-one machine or PoE switch. A single panel is disconnected and all other rooms are fine. The three most common reasons are ranked by probability.:

The first one is also the real murderer of my family.: The network cable is loose at the switch end. There are many wires in the weak current box. When I was arranging the wires, my hands were too thin and I tied the wires too tightly. The clamping spring of one of the crystal heads was pushed out half-way. It usually made good contact, but one day when I touched the box, it fell to the critical point. The symptom is that the connection in a single room is lost. When you plug it back in and hear a "click", everything is fine. Cable management requires a balance between "neatness" and "top to bottom". I later made up this lesson specifically in the article on organizing weak current boxes.

second: The PoE power supply port is burned out or the power supply is insufficient. The panel AP is powered by network cables. If the AC is an all-in-one machine with a PoE port, and a certain port is hit by a lightning surge or short circuit, one port will be burned separately, and the other ports will remain as normal. Judgment method: Change the cable in the study room to the empty PoE port next to it and try it. The renovator of my neighbor's home drilled a hole for the network cable in the ceiling and short-circuited it. After that, there was no power from that outlet - changing the outlet solved the problem.

third: The crystal head is oxidized. After using the line for several years, the contact resistance of the crystal head reed becomes oxidized and increases, and the performance is often "good and bad" instead of simply disappearing. If your home is chronically disconnected, try to reset it first. I have written a complete line sequence and technique for pressing the crystal head. Network cable crystal head wiring , Memorizing one type of T568B is enough, and by the way, you can check whether the electrician has pressed it into four cores - four cores run at 100M, and no matter how new the panel AP is, it will be useless.

These three actions are all completed in the weak current box, and none of them need to touch the panel of the room. I unplugged and plugged in four wires in the weak current box that day as a troubleshooting method. I found out which wire it was in ten minutes - I left the other three wires that were all good and unplugged the one in the study room and plugged it in again. The study panel in the AC list immediately jumped back to "Online".

Not bad yet, it’s time to remove the panel: Look at two things

It is confirmed that there is no problem with the weak current box end, changing the port is useless, and the panel in the AC list is still not online, then it is worthwhile to remove the panel. It is not difficult to disassemble the panel AP. Most of the time it is two screws hidden under the panel, or you can directly pull out the frame, but before disassembly, take a photo to remember how the wires are routed.

There are two main things to look at when taking it apart. The first is the indicator light on the back of the panel. A normally powered panel AP has a working light. If it is on, it means that the PoE power is delivered. The problem is most likely with the panel motherboard. Return it to the factory or replace it with one of the same model. ； If the light does not light up, it means that the electricity has not arrived at all. It is still a matter of wires - focus on checking whether there is a connector in the middle of the wire, especially if the electrician connected the wire in the ceiling during decoration to save trouble. Oxidation of the connector is a classic hidden disease that causes the panel AP to lose connection.

The second is to check the status of the reed in the network port. The night I dismantled the study panel, even though I confirmed that the problem was with the weak current box, I still took a look at the network port of the panel. There was gypsum powder residue from the decoration in the reed, and I blew it away with air. This kind of slag does not usually affect the reed, but it will slowly wear down the reed, which is a hidden danger that can be easily eliminated.

Is the panel AP itself broken? There is a more trouble-free verification method.: Remove the panels from other rooms and replace them with the disconnected room. It's good to have it replaced, but the panel is broken. ； Replacing it still doesn't work, the wiring is bad. One cross-exchange can directly resolve the dilemma of "panel or cable", which is much faster than removing the panel twice and trying again.

The finishing touches after repairs: Don't be lazy with two

The first closing: Label the wires in the weak current box. I suffered the disadvantage of not having labels. During that inspection, I just tried to identify "which root is the study room" by pulling it out one by one. When arranging cables, spend more than ten yuan to buy a pack of label paper. Write the room name on both ends of each cable. Stick one on one end of the weak current box and one end of the room. This will save you a whole night if something goes wrong two years later. I made a rule about this when I finished arranging the lines, but the one in the study was missed and I was punished directly this time. I have written the complete method of organizing cables in the article on organizing weak current boxes. You can read the two articles side by side.

The second ending: After the single-room WiFi is restored, go into the AC backend to double-check the channel and power. During the process of losing and recovering the panel, the AC may have reassigned channels to this panel. If it collides with the next room, although it can be used, the speed will be inexplicably lower. Don't bother checking in the dark. Just scan the channels in each room in the list and you'll be fine if you miss them. In addition, if you are still confused about whether to take AC+AP, I will How to choose between AC+AP and Mesh There is a complete comparison account in that article, and pitfalls such as the depth of the bottom box and occlusion and heating are also included.

Put this sequence into one sentence: First, plug the computer into the network port to distinguish "wired or wireless" → Check the AC backend to see if the panel is online → Reinsert the port in the weak current box → If it doesn't work, remove the panel for cross-exchange. If the WiFi in a room is gone, there is really no need to buy a new panel. That night, I went from being frustrated that "it will definitely cost 300 yuan to replace the panel" to hearing a "click" when the panel in the AC list came back online. The entire troubleshooting process took 40 minutes and cost zero.