iPhone 17 Pro Max No SIM or Invalid SIM: Board-Level Guide to SIM Card Paths (Supply, Reset, Clock, Data, Detect)
🚀 Introduction: Why SIM Card Faults Hide on the Board
On the iPhone 17 Pro Max, No SIM, Invalid SIM or a SIM that works only sometimes are often blamed on the tray or the reader. Very often the real fault is on the logic board: a missing SIM supply, a broken data line or a damaged detect line. This short guide follows the six color-coded SIM nets from the Borneo Schematics reference shown in the video, so you can test them in the right order.
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| iPhone 17 Pro Max SIM Card Repair: Schematic-Based Path Tracing with Borneo Schematics |
📱 iPhone 17 Pro Max No SIM Card Detected: Full Board-Level Tracing Guide for Technicians
💡 Technical note: in the net names, BB means the baseband, SIM1 is the first SIM interface and CONN marks the SIM connector side. Some regional iPhone models are eSIM-only, so confirm that your unit really has a physical SIM tray before you start.
📋 iPhone 17 Pro Max: Key Specifications
| Feature | Detail |
|---|---|
| Model | Apple iPhone 17 Pro Max |
| Announced / Released | September 2025 |
| Chipset | Apple A19 Pro (3 nm class) |
| Display | 6.9-inch Super Retina XDR OLED, 2868 × 1320 px, ProMotion up to 120 Hz |
| Memory / Storage | 12 GB RAM; 256 GB, 512 GB, 1 TB, 2 TB |
| Connector / OS | USB-C; iOS 26 at launch |
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| iPhone 17 Pro Max Invalid SIM: Supply, Reset, Clock and Data Lines Explained |
ℹ️ Specs are summarized from public sources such as GSMArena and Apple. Confirm details on the official page before quoting them to a customer.
⚠️ Legal Disclaimer
This content is intended exclusively for licensed repair professionals and certified repair workshops. Board-level work involves live voltages and delicate microsoldering. Always disconnect the battery before probing, use a current-limited DC power supply, and respect device ownership and local laws. Advancedsetting.com is not responsible for damage resulting from misuse of this information.
🗺️ How the SIM Circuit Works
The SIM interface has three jobs. If any one fails, the phone reports no SIM or no service.
- Power: the SIM supply (
PP_UIM1_LDO11_CONN) and a 1.8 V rail (PP_1V8_LDO6) power the SIM and its interface. - Communication: the baseband sends reset and clock to the SIM and exchanges data with it in both directions.
- Detection: a detect line (
IO_BB_FROM_PSIM_DETECT_CONN) tells the baseband that a SIM tray is present.
🔍 The Six SIM Nets
| Net | Function (per net name) | Fault symptom |
|---|---|---|
PP_UIM1_LDO11_CONN | SIM1 supply from LDO11 to the SIM connector | No SIM, Invalid SIM |
PP_1V8_LDO6 | 1.8 V rail from LDO6 used by the SIM interface (confirm exactly what it feeds in your schematic) | SIM not read, may affect other 1.8 V circuits |
IO_BB_TO_SIM1_RESET_L_CONN | SIM reset line, active low, from the baseband to the SIM | SIM never starts, No SIM |
IO_BB_TO_SIM1_CLK_CONN | SIM clock from the baseband to the SIM | Invalid SIM, unstable detection |
IO_BB_BI_SIM1_DATA_CONN | Bidirectional SIM data line between the baseband and the SIM | No service, SIM works intermittently |
IO_BB_FROM_PSIM_DETECT_CONN | SIM tray detect signal from the connector to the baseband | No SIM even with a good SIM inserted |
🔧 Workshop note: voltages are not given in the names, except 1.8 V. Confirm pin numbers and expected values in Borneo Schematics for your board revision and compare with a known-good unit.
🧪 Components on the Path
| Component | Role | Common fault | Basic test |
|---|---|---|---|
| SIM connector / tray reader | Contacts for the SIM and the detect switch | Bent or corroded pins, damaged detect contact | Microscope inspection, tray test |
| LDO and its output capacitor (SIM supply) | Produce the SIM supply | Missing or low supply, short | Measure the supply with a SIM inserted; short test |
| ESD / filter parts on the lines | Protect and filter reset, clock, data and detect | Leakage, short or open | Diode mode against ground, compare with a good board |
| Baseband side | Drives reset, clock and data, reads detect | No activity on the lines with good supply | Check continuity from the connector to the baseband side |
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| iPhone 17 Pro Max SIM Detect Line and SIM Supply: How to Find the Fault Fast |
🛠️ Quick Diagnosis Workflow
- Try a known-good SIM and tray, and inspect the connector under a microscope.
- Use a DC power supply and compare boot current; a high fixed current suggests a short on a SIM rail.
- In Borneo Schematics, highlight the six nets and measure the SIM supply and the 1.8 V rail with the SIM inserted.
- Check the detect line idle level, then insert and remove the tray and watch it change.
- Check reset, clock and data for continuity and compare diode-mode readings with a known-good board.
- If a rail is shorted, inject limited voltage and find the hot part with a thermal camera; repair broken lines with a jumper wire.
❗ Common Symptoms and Likely Causes
| Symptom | Likely cause | Action |
|---|---|---|
| No SIM | Detect line, supply or connector | Check detect level and the SIM supply |
| Invalid SIM | Supply, reset or clock problem | Measure the supply and check reset and clock lines |
| SIM works then drops | Data line or loose connector contact | Inspect the connector, check the data line |
| Works with one SIM only | Dirty or damaged contacts on the reader | Clean and inspect, then test with a known-good tray |
| Fault appeared after a drop or liquid | Bent pins, lifted pads or corrosion | Microscope inspection and line tracing |
💡 Bench tip: always test with a known-good SIM first, and photograph the board before removing shields. Record healthy readings from every board; your library becomes your donor board.
🎬 Video Tutorial
The video follows the six SIM nets on the board and shows the order of the tests.
🔗 Trusted External Links
- Apple: iPhone 17 Pro and Pro Max technical specifications
- GSMArena: iPhone 17 Pro Max review
- Apple Support
- Apple Self Service Repair
- iFixit: iPhone repair guides and teardowns
- Wikipedia: SIM card
- Wikipedia: ISO/IEC 7816 (smart card standard)
- Borneo Schematics
Each link opens in a new tab.
⬇️ Download Section
| File | Format | Link |
|---|---|---|
| iPhone 17 Pro Max SIM Card Paths: Net Reference | PNG / PDF | [download link] |
🙏 Special Thanks to Borneo Schematics
The board views and color-coded nets in this guide come from Borneo Schematics, an online schematic and board-view platform for mobile repair. Thank you to its team for the work behind this tool.
If you want to follow along and work with this program comfortably and without limits, we encourage you to subscribe to Borneo Schematics and support the team.
🌐 Visit www.borneoschematics.co.id☕ Support Our Work
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☕ Buy us a coffee on PayPal❓ FAQ
Why does my iPhone 17 Pro Max say No SIM with a good SIM? Start with the detect line and the SIM supply, then the connector.
Can I trace SIM lines without a donor board? Yes. A schematic and board-view tool lets you follow each net and compare readings with known values.
