Samsung Galaxy S3,Samsung problems

Method to Resolve Samsung Galaxy S3 SIM and MMC Problem

Method to Resolve Samsung Galaxy S3 SIM and MMC Problem

In the following lines you will get to know about all the possible Samsung Galaxy S3 Sim Card and MMC problems as well as their solutions in the best possible manner.

However before you begin to solve Sim card and MMC problem in your Samsung Galaxy S3 it is really very important for you to identify them in first place. Below you can see the figure indicating which circuit is of Sim card and which is of MMC.

Samsung Galaxy S3 Sim and MMC Card identification


Sim card problems

Following are some of the common Samsung Galaxy S3 Sim card problems:

  • Sim Fails to read
  • It shows the error “Insert SIM Card”.
  • Sim not reading properly.

MMC problem

Following are some of the Samsung Galaxy S3 MMC problems:

  • MMC not inserted
  • Card corrupted
  • Fail to read
  • Hanging problem while inserting card.

Reasons of Problems

For Sim Card

  • Sim card might be out of order.
  • Sim contacts are not able to make proper contact with Sim card jacket’s contacts.
  • Sim card or card holder pins might be dirty, clean both of them and check.

For MMC Card

  • MMC might be faulty or the content of the card might be corrupt.
  • Viruses or bad sectors in MMC might also be the cause of this problem.
  • Any of the hardware components might be faulty.


For SIM Card

In order to resolve all these problems, all you have to do is to follow the following steps:

  • Use any other good sim card in your Samsung Galaxy S3
  • Visually check SIM card holder for possible damage and also clean it

For MMC Card

  • Use any other good MMC card, if the second one works fine then it means the previous card was faulty.
  • In case the message is something like “Memory Card Corrupt, need to format” then it means that your memory card has viruses or bad sectors, and you need to format it in order to get it working.

Samsung S3 Sim and MMC circuit configuration

Hardware Solution

For Sim Card

  • Fix all the misaligned pins or you can also chose to replace PCB holder too.
  • Check SIM voltage when the SIM card is inserted, it should be around 1.8v.
  • Trace every VSIM, SIM reset, SIM clk and SIM IO and Ground pins (as shown in above Figure)
  • Pin details as mentioned in above figure (from top right) includes: pin2 ground, 3 VSIM, 4 sim clk, 5 sim data.

For MMC Card

  • Change MMC PCB strip and reinsert memory card and check whether it is working or not.
  • If MMC is still not working then re solder MMC board connector
  • Reheat or replace MMC IC which is mounted at top right of MMC/SIM connector this is surely going to resolve the problem.


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