Which part of the phone has to do with SIM functionality

Question

Samsung Galaxy S21+

Released in January of 2021. Identified by model numbers SM-G996B, SM-G996B/DS, SM-G996U, SM-G996U1, SM-G996W, SM-G996N and SM-G9960.

crwdns2934591:020crwdne2934591:0 crwdns2934593:0crwdne2934593:0 | crwdns2947278:018crwdne2947278:0 crwdns2947270:0crwdne2947270:0

Forrest Lambert @forrestlambert

crwdns2934065:0crwdne2934065:0: 1

1

crwdns2931729:0crwdne2931729:0: Mud 17, 2024

crwdns2933897:0crwdne2933897:0

Which part of the phone has to do with SIM functionality

I'm kind of having the same issue, but calls and data work. S21 plus, when i turn the phone on the screen to register comes up and does it thing, then fails, but as stated, calls still work etc. Is that a sim card reader fault or mother board issue?

And it fails after. But still have 5G and data. Does it every time I turn the phone on.

Safe mode didn’t work. But I did notice when you turn the phone on, whatever chip is under the cover is getting super super hot. I don’t know if that’s a partial short, I don’t have my air station yet to pull the cover off. But that might be the issue. Would you have an idea what chip or chip’s are under that?

crwdns2934089:0crwdne2934089:0 crwdns2934093:0crwdne2934093:0

crwdns2934109:0crwdne2934109:0

crwdns2853045:0crwdne2853045:0 crwdns2853046:0crwdne2853046:0

crwdns2889612:0crwdne2889612:0 0

crwdns2944067:09crwdne2944067:0

Hi @forrestlambert

What do you mean by ..."i turn the phone on the screen to register comes up and does it thing, then fails,.....", what exactly happens when it fails?

If calls still work then the SIM card reader is still doing it's primary function i.e. phone can read SIM card and this allows access to the mobile phone network

crwdns2934271:0Mud 17, 2024crwdnd2934271:0 jayeff crwdne2934271:0

You have an email i can send a video too, or Facebook messenger? I can show you that way.

crwdns2934271:0Mud 18, 2024crwdnd2934271:0 Forrest Lambert crwdne2934271:0

@forrestlambert

Post the video in your question above.

Here's how on ifixit Adding images to an existing question

crwdns2934271:0Mud 18, 2024crwdnd2934271:0 jayeff crwdne2934271:0

Video is up top.

crwdns2934271:0Mud 23, 2024crwdnd2934271:0 Forrest Lambert crwdne2934271:0

@forrestlambert

Does it still do this if you start the phone in safe mode?

crwdns2934271:0Mud 23, 2024crwdnd2934271:0 jayeff crwdne2934271:0

crwdns2934275:04crwdne2934275:0

crwdns2934285:0crwdne2934285:0

crwdns2933313:01crwdne2933313:0

Hi @forrestlambert

What do you mean by ..."i turn the phone on the screen to register comes up and does it thing, then fails,.....", what exactly happens when it fails?

If calls still work then the SIM card reader is still doing it's primary function i.e. phone can read SIM card and this allows access to the mobile phone network — jayeff
You have an email i can send a video too, or Facebook messenger? I can show you that way. — Forrest Lambert
@forrestlambert

Post the video in your question above.

Here's how on ifixit Adding images to an existing question — jayeff
@forrestlambert

Does it still do this if you start the phone in safe mode? — jayeff

score 1 · Answer 1 · 2024-05-23T18:05:57-07:00

crwdns2934057:0crwdne2934057:0

jayeff @jayeff

crwdns2934065:0crwdne2934065:0: 499,4crwdns2936485:0crwdne2936485:0

11

388

1,5crwdns2936485:0crwdne2936485:0

crwdns2931729:0crwdne2931729:0: Mud 23, 2024

crwdns2933897:0crwdne2933897:0

Hi @forrestlambert

Since it is a used phone, go to Settings > General Management > Reset > Reset Network Settings > Reset Settings > Reset

Hi @forrestlambert

See p.3 of the pcb layout to view all the ICs under the shield.

Find out which one is getting hot and then using its designation from the board layout, search for the designation in the service manual to see what its used for.

If the IC or another component is faulty, here's the parts list. Search online for the part number for the component, to find suppliers.

crwdns2934105:0crwdne2934105:0

crwdns2853045:0crwdne2853045:0 crwdns2853046:0crwdne2853046:0

crwdns2889612:0crwdne2889612:0 1

crwdns2944067:09crwdne2944067:0:

I've also done that a few times.

crwdns2934271:0Mud 24, 2024crwdnd2934271:0 Forrest Lambert crwdne2934271:0

@forrestlambert

The only thing that I can suggest now is to back up the phone to a computer and perform a factory restore on the phone as this will determine if it is a software or a hardware problem

If you have a Google or Samsung account associated with the phone you will need to remember the account ID and password to re enter the phone to set it up again after the reset.

If you decide to do this then once the restore has been completed, check if it works OK.

If it does then the reset has resolved the problem. If it still fails then it's a hardware problem.

crwdns2934271:0Mud 24, 2024crwdnd2934271:0 jayeff crwdne2934271:0

I will give all that a try tonight. I switched phones for now, Ill update tonight. Thanks for all your help sir.

crwdns2934271:0Mud 24, 2024crwdnd2934271:0 Forrest Lambert crwdne2934271:0

I posted a picture last week. What i noticed is, when i turn the phone on, on the front side of the board, the chips under the cover get stupid hot, then after a while it kind of cools but now nothing works.Whar are the chips on the back side of the phone when u take the back glass off? Maybe a partial short?

crwdns2934271:0Kho 1, 2024crwdnd2934271:0 Forrest Lambert crwdne2934271:0

@forrestlambert

Look at the pcb board layout linked above to find out what the Chip ID is and then check what they're used for using the service manual is probably the best way to find out.

crwdns2934271:0Kho 1, 2024crwdnd2934271:0 jayeff crwdne2934271:0

crwdns2934275:04crwdne2934275:0

crwdns2934285:0crwdne2934285:0

Samsung Galaxy S21+

Which part of the phone has to do with SIM functionality

Update (05/19/24)

Update (05/27/24)

crwdns2933313:01crwdne2933313:0

Update (05/27/24)

crwdns2934229:0crwdne2934229:0