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Released September 16, 2016. Models A1661, A1784, and A1785. Available in 32, 128, or 256 GB configurations in Rose gold, gold, silver, black, jet black, and (Product)Red.

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iPhone 7 Plus keeps searching for service

I received an iPhone 7 Plus to repair and resell. It isn’t set up yet, but it keeps searching for a signal, while the sim card isn't inserted. Inserting a sim card doesn't make a difference though, it keeps searching for a signal. When I try to set the phone up, it tells me "Unable to Activate" (see the picture below). Does anyone know what the problem might be and what I should check? What should I check with my multimeter? Is this the baseband chip that's causing problems? I am new to logic board repair / micro soldering, but I do want to do it myself and I got the equipment.

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Your phone has more than likely had a failed audio IC repair. The audio IC has had too much heat applied to it causing the Baseband CPU’s solder balls to expand resulting in the problem you are having.

This has nothing to do with the Antenna. If you type *#06# into your keypad does the IMEI display? If it doesn’t it will confirm it. There is no simple fix for this problem unless you are an experienced microsolderer.

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Check the antenna bars. They might be obstructed.

If that doesn’t work, try ejecting, cleaning, and re-inserting the SIM card.

I personally don’t have 7 plus, so this is some minor textbook stuff that not everyone knows.

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The antenna bars do look a bit damaged. Could this be the problem?

https://imgur.com/xS9aTJD

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Step 1: Basic Checks

  1. Toggle Airplane Mode
    • Go to Settings → Airplane Mode → turn ON for 30 seconds, then turn OFF.
  2. Restart your iPhone
    • Press and hold the Power + Volume Down buttons until the Apple logo appears.
  3. Check SIM Card
    • Remove the SIM tray, clean the SIM, and reinsert.
    • Try another SIM card to rule out a carrier issue.
  4. Update Carrier Settings
    • Go to Settings → General → About; if an update appears, accept it.
  5. Update iOS
    • Make sure the phone has the latest iOS version.

Update (08/14/25)

Step 2: Reset Network Settings

  • Settings → General → Transfer or Reset iPhone → Reset → Reset Network Settings
  • This clears Wi-Fi, VPN, and cellular settings without deleting your data.

Step 3: Detecting Hardware Failure

The iPhone 7/7 Plus often develops a Baseband IC fault where the cellular modem stops responding.
Signs it’s hardware:

  • In Settings → General → About, the Modem Firmware field is blank.
  • Restoring iOS in iTunes doesn’t fix it.
  • “Searching…” or “No Service” happens everywhere, not just in weak-signal areas.

If that’s the case, the only fix is motherboard-level repair (baseband chip reballing or replacement) by a skilled technician

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