Help Phone doesn't work on some cities

[heberrc]

On my home town my Samsung Galaxy S7 Edge works perfectly, but when I travel to some cities it presents the following problems

• No internet access. Neither WiFi nor 4G work.
• Overheating
• Battery discharges very quickly.
• In one case the keyboard was unresponsive.

In one city in a country it works fine, but in another city in the same country it doesn't.
Any ideas what could cause this strange behaviour?

 

[Brian706]

Probably just the network. There's probably not supported bands in every city you are visiting and you simply have no service. That's probably related to the battery drain and overheating as well. Your phone is probably constantly trying to connect to something.

 

[mikedt]

Are you in North Korea perchance?

 

[svim]

Different carriers and different countries rely on different cellular networks that work using different frequencies. Those combinations vary widely and most branded phones contain only the necessary radio chips inside for the network the respective carrier supports. There are some 'unlocked' phones that can be used with different carriers and a few 'universal' models that work on an even larger number of cell networks, but for your S7E try using this site to check it's compatibility:
https://willmyphonework.net/

 

[svim]

Are you in North Korea perchance?

The OP's profile indicates Brazil.

 

[heberrc]

Thank you very much for the replies.
Today two Samsung smartphones originally from Maceió, a Brazilian city, both from TIM carrier, were in Campinas (another Brazilian city). Later on, they were in Rio de Janeiro, where both operated withou problems. TIM operates in the same frequencies on all these cities. One worked flawlessly the other presented the problems I reported. Can network differences explain this?
Furthermore, in Panama City on flight mode only using WiFi the smartphone presented these problems.

 

[Brian706]

Thank you very much for the replies.
Today two Samsung smartphones originally from Maceió, a Brazilian city, both from TIM carrier, were in Campinas (another Brazilian city). Later on, they were in Rio de Janeiro, where both operated withou problems. TIM operates in the same frequencies on all these cities. One worked flawlessly the other presented the problems I reported. Can network differences explain this?
Furthermore, in Panama City on flight mode only using WiFi the smartphone presented these problems.

Well, you didn't give us all the information in the original post. So all we could do is make assumptions and give our best guess of the problem. Of you're using two identical phones on the same carrier and one is working and one isn't... I think you answered your own question. One of them is faulty.

Actually, when you say two Samsung devices, are they the same Samsung device or different? Just because they are both Samsung devices doesn't mean they support the same bands.

Did you try using the link posted above for willmyphonework? That site will tell you whether or not your device should work in a specific area.

 

[heberrc]

Thank you for your reply.
The smartphones I mentioned actually belong to two relatives I am trying to help.
The first time this problem occurred was in the beginning of this month in Panama City. This mobile had been before in Campinas and São Paulo and showed no problems until the day before yesterday.

Well, you didn't give us all the information in the original post. So all we could do is make assumptions and give our best guess of the problem.

Sorry about that.

Of you're using two identical phones on the same carrier and one is working and one isn't... I think you answered your own question. One of them is faulty.

One is an S5 and the other is an S7 Edge, which is the one that presents the problem.

Did you try using the link posted above for willmyphonework? That site will tell you whether or not your device should work in a specific area.

Thank you for letting me know about this site. According to it, this S7 Edge model is fully compatible with both countries and carriers.

 

[svim]

OK now that we have more details your problem is pretty odd. As your S7 Edge is working fine in your home city and those problems are only when you're traveling elsewhere, perhaps there's an issue with the SIM cards for the other carriers. Do they look any different than the SIM you use at home? Does just rebooting your phone make any difference with the over-heating issue? If it's warming up and the battery is draining faster it does sound like part of that is just the phone is trying to pick up a wireless connection.
Also, I missed the part where you also mentioned a problem with WiFi when you're traveling. Is this a matter where your phone isn't detecting any WiFi networks or is it an issue where you're having a problem connecting to them?
Some WiFi networks, often public WiFi, rely on a system where to connect you need to go through a web authentication page to then be able to actually login into the network (referred to as a 'captive portal login').

 

[heberrc]

This smartphone belongs to a relative that I am trying to help. It seems that I had the facts slightly wrong. Let me try to straighten them
An S5 and the S7 Edge went together to several cities in Brazil (my home country) and both worked just fine. They use the same provider. In the beginning of this month the S7 was taken abroad and during a stop in Panama it presented these problems for the first time:

• Overheating
• Battery discharges very quickly.
• Keyboard unresponsive.

The mobile was on flight mode, just using WiFi. It was only possible to send voice messages, as the keyboard didn't work. No local network was used in Panama, just WiFi. In the final destination the S7 worked without any issues.
This week in São Paulo the mobile presented again the same problems. On the return flight, there was a stop in Rio de Janeiro and there the S7 worked fine as well in its home city. The S5 was on the same trip and had no problems.
During all these events the SIM card was the same.

 

[svim]

Instead of using Airplane mode when in transit, maybe try just disabling either WiFi or mobile data (whichever isn't in use). It sounds like your phone is just trying to connect to something that's not available, possibly tied to some oddball option buried in the Settings menu that could be just disabled completely. Samsung does love to add 'enhancements'.
As for the keyboard becoming unresponsive, does it become usable again right after your phone has online connectivity again (either WiFi or mobile data)?

 

[heberrc]

I thought that airplane mode would switch off all radios. Anyway, the S7 should work normally in other cities in the same country just as the S5 or my S8 do.

The keyboard became unresponsive right after switching on.

 

[svim]

Airplane mode is supposed to disable are the radios, that's why I suggested you use either WiFi or mobile data as you did state, "...The mobile was on flight mode, just using WiFi. It was only possible to send voice messages, as the keyboard didn't work..."

And as @Brian706 implied earlier, different Samsung devices will support different bands. The hardware inside different models often varies, sometimes quite a bit, even when from the same manufacturer. Also different versions of Android will have varying support and utilities, plus cellular networks are evolving too.

 

[heberrc]

Thank you for the reply.
Unfortunately I am lost here. I have verified through https://willmyphonework.net/ that this specific model is 100% compatible with Brazilian carrier TIM, that operates throughout the country. Why a mobile that worked in a city one day would stop working on the same city only a few days later? The S5 worked before and also worked yesterday.

 

[svim]

Have you contacted someone at TIM? As it is their cellular network they might have some insight on what's happening.

 

[heberrc]

As the problem first started in Panama I didn't think the TIM carrier would know how to solve the problem.