Intermittent Fiber Optic Connection: LOS LED Flashes Red on Router

Hello,
I don't know if I'm in the right section - if not, I apologize in advance and please place the topic in the right one.
Now to the point...:
I recently moved into a new apartment, where we were offered FIBER OPTIC - internet + TV.
I agreed, the gentlemen from the company from which I got the service ran the fiber optic cable, which was hidden behind the floor strips (it was not bent), connected it to the router, there is WiFi, there is a TV signal - everything works fine.
After a few days of use, suddenly there is no Internet and TV signal, once there is no signal for half a day, and for the second half everything works again, once it does not work all day, and the next day everything works again, and sometimes everything works, and then for 2 days -3 hours no signal (does not work), then comes back and works again.
When there is no signal, the LOS LED on the router flashes red.
When there is a signal, the red LED does not blink and does not light up.
Of course, specialists from the company from which I got the service were called. They came and measured (probably because I'm not an expert) the fiber flow - it turned out to be OK. They thought about it, went to their boxes and came up with an idea, or rather a solution, here it is:
- the floor panel or skirting board presses on the optical fiber, so sometimes there is a signal, sometimes there is not. And they added that they would replace my optical fiber after New Year's Eve, leaving me on New Year's Eve instead of Polsat (or another channel) with silence...
My question: IS THIS POSSIBLE?
I would understand if the optical fiber was interrupted, but then there would probably be no signal at all for several days, and sometimes there is, sometimes there is no signal. Besides, they measured everything and said everything was fine, and now I would have to tear off the skirting boards again to install a new fiber optic cable, which is not known whether it will work properly...
COULD IT BE THEIR FAULT, E.G. SERVERS THAT SOMETIMES I HAVE A SIGNAL AND SOMETIMES I DO NOT?

Best regards and I would like to ask for an answer

Maybe the fault lies with the modem or power supply.

I'm betting it's the supplier's fault. Fiber optic is not a cable that if it breaks, sometimes it will touch it, sometimes it won't . Once it breaks, it just sneezes. MZ, replacing the optical fiber will not help (maybe I'm wrong). Especially since no one seems to move it and the bending radius doesn't change over time. I remember that in our network, when we built the main threads on optical fibers, we had a problem with strong signal attenuation in one thread. It turned out that when I was welding the fibers, I accidentally bent the pigtail too much on the splice tray. . And the attenuation increased dramatically, but the signal was still there, but weak. If you have it sometimes and sometimes not, I would rather bet on a faulty modem at your home or on the other side, at the operator's. Possibly some connectors on one side...

kranzio wrote:

Maybe the fault lies with the modem or power supply.

Everything is working, even the specialists from the company checked the equipment they provided, everything blinks green (power wlan, etc.) even when there is no signal, but when there is no signal, there is also this red diode next to LOS... Magic, I wonder about the text experts regarding the panels, whether something may be pressing and that's why the connection is interrupted and sometimes it works normally - for me it's strange, if only because there is about 5-8 mm gap between the panels and the walls where the fiber optic cable looks like a string is inserted, so I don't even know if it has minimeter diameter...

Is the power supply external or in the modem? Maybe the end of the fiber optic plug that is plugged into the modem is badly connected. What modem do you have for fiber optic?

What is the signal level is the question, if it is e.g. -25 or -26 (GPON), it is too much bent somewhere, a bad weld or pigtail, the adapter is damaged.

kranzio wrote:

Is the power supply external or in the modem? Maybe the end of the fiber optic plug that is plugged into the modem is badly connected.

You probably won't get a bad end of the fiber optic cable, maybe some crap happened. The fitter does not make the ends, he only welds on the finished pigtail. But I would rather bet on a problem with the active device. You know, if someone moves the plug or cable and sometimes it works, sometimes it doesn't, that's OK, but if everything lies still, it's probably not a problem...

dzidek1968 wrote:

I'm betting it's the supplier's fault. Fiber optic is not a cable that if it breaks, sometimes it will touch it, sometimes it won't . Once it breaks, it just sneezes. MZ, replacing the optical fiber will not help (maybe I'm wrong). Especially since no one seems to move it and the bending radius doesn't change over time [...] If you have it sometimes and sometimes not, I would rather bet on a faulty modem at your house or on the other side, at operator. Possibly some connectors on one side...

The optical fiber was not moved after its installation, as you say, at the beginning everything worked without any problems, I will ask these specialists about the new modem, maybe the fact that everything lights up nicely in green does not mean that everything works OK in it. Although the specialists from the company said that everything ok, but if they were able to squeeze in a story about the panels, who knows...

What modem did your friend install?

I know how it works, I was a supplier myself for several years. I won't deny that if you have many clients, you probably don't look for problems yourself. I don't want to say that I'm pissing off the customer, but no one replaces the equipment in everyone's home right away, because you won't be able to do it even if you do gymnastics. . First, less radical measures are taken, i.e. replacing the connectors, checking the cable routing, etc. Anyway, I will tell you that these types of faults (sometimes it works, sometimes it doesn't) are the most nasty. I'd rather have something just go wrong at the client's and replace it than have to go back ten times and it worked like hell every time we came back.

dzidek1968 wrote:

You probably won't get a bad end of the fiber optic cable, maybe some crap happened. The fitter does not make the ends, he only welds on the finished pigtail. But I would rather bet on a problem with the active device. You know, if someone moves the plug or cable and sometimes it works, sometimes it doesn't, that's OK, but if everything lies still, it's probably not a problem...

That's right, it lies motionless because, as I wrote, it worked, but then something happened later. Today, for example, there was no signal from morning until 6:40 p.m., and now there is - magic...

Added after 5 [minutes]:

kranzio wrote:

What modem did your friend install?

huawei echolife hs8546v

See this manual Link on the behavior of PON and LOS diodes. Instructions from another modem, but I think the principle is the same in yours. Unless you have the manual for yours.

Typowy Mirek wrote:

- the floor panel or skirting board presses on the optical fiber, so sometimes there is a signal, sometimes there is not.

Nonsense. If the installer thinks so, he should work elsewhere.
In my opinion, the fault lies with the signal provider.
M

kranzio wrote:

See this manual Link on the behavior of PON and LOS diodes. Instructions from another modem, but I think the principle is the same in yours. Unless you have the manual for yours.

Thanks, now, as I wrote earlier, everything is working from 6:40 p.m., so PON is on correctly, and LOS is not on at all. If the signal disappears again, I will write here what is happening, how they blink (fast or slow) and what it means with this instruction, maybe someone will then translate it into common sense. I will definitely describe everything because sooner or later the signal will probably disappear. I will try to keep you updated on everything

This is the biggest disadvantage of fiber optics - if something goes wrong, you basically can't do anything yourself, you have to call the service and, as is usually the case in life, when it shows up, everything works without a problem. It is also a pity that you did not pay attention to the signal level from the reflectometer, if such a measurement was made.

As for the theory that sometimes you press something and then it doesn't work, and other times it works because there is no pressure - it seems moderately probable to me. For your part, you can basically check one thing - whether the cable runs freely along the route of sharp bends - if there are any, try to arrange it so that it runs as loosely as possible. Another issue is if you have a supply of cable in your apartment and I know that some companies do this and leave the cable rolled up in a coil at the customer's place. Unfortunately, if the diameter of the circle is too small, the signal on the cable begins to be significantly attenuated. So if you have a spare, you can try to loosen it slightly by increasing the diameter of the circle. Of course, there is no guarantee of success, but if it doesn't work and you don't know why, you don't risk anything and maybe you will find something.

By the way, it's a pity you didn't talk to me, maybe they could have made a makeshift solution so that you would have a working service for a few days.

As for the nomenclature, the optical fiber device is an ONT, not a modem.

seb235 wrote:

... and I know that some companies do this and leave the cable wrapped in a coil at the customer's place. Unfortunately, if the diameter of the circle is too small, the signal on the cable begins to be significantly attenuated. So if you have a spare, you can try to loosen it slightly by increasing the diameter of the circle.

Honestly, I don't know how tightly the cable would have to be wound and how many turns it would have to have to attenuate the signal . I still remember when we bought a welding machine and, as it happens with big children , we had some fun, I wound individual fibers around my finger like a spring and the optical fiber didn't break, but also attenuated it quite a bit. I don't know how tightly the installer would have to wind the cable to make the signal disappear ). Therefore, as I wrote earlier and was confirmed by several colleagues, I do not believe that the optical fiber is to blame and I think it is the equipment's fault. Unfortunately, switches, converters, modems and optical modules can hang. If it happens once, e.g. after a temporary power outage, it's OK, but if it happens more often, the device needs to be replaced. These are costs, which is why the operator, as I wrote, first tries to "hide" the situation, and if it doesn't help after a while, then he will replace something. This is how it works, I know from practice .

dzidek1968 wrote:

seb235 wrote:

... and I know that some companies do this and leave the cable wrapped in a coil at the customer's place. Unfortunately, if the diameter of the circle is too small, the signal on the cable begins to be significantly attenuated. So if you have a spare, you can try to loosen it slightly by increasing the diameter of the circle.

Honestly, I don't know how tightly the cable would have to be wound and how many turns it would have to have to attenuate the signal . I still remember when we bought a welding machine and, as it happens with big children , we had some fun, I wound individual fibers around my finger like a spring and the optical fiber didn't break, but also attenuated it quite a bit. I don't know how tightly the installer would have to wind the cable to make the signal disappear ). Therefore, as I wrote earlier and was confirmed by several colleagues, I do not believe that the optical fiber is to blame and I think it is the equipment's fault. Unfortunately, switches, converters, modems and optical modules can hang. If it happens once, e.g. after a temporary power outage, it's OK, but if it happens more often, the device needs to be replaced. These are costs, which is why the operator, as I wrote, first tries to "hide" the situation, and if it doesn't help after a while, then he will replace something. This is how it works, I know from practice .

This is what I'm leaning towards the most...
As I wrote earlier, guys, there was no signal since the morning, suddenly at 6:40 p.m. it is there and still working. As soon as it stops working, I will write, according to the instructions sent by my colleague Kranzio, what frequency the PON and LOS diodes are flashing, and what the instructions say it may mean.
Well, some magic...