EivoTech Laptop & Mobile Repair Master Course
Mobile Repair Course — Part 27
Smartphone Wi-Fi + Bluetooth + GPS + NFC Advanced Diagnostic Workflow
Chapter 27: Wireless Fault ko IC Fault Kehne ke Bajaye Digital Side aur RF Side Mein Divide Karna
Smartphone wireless system mein Wi-Fi, Bluetooth, GPS/GNSS aur NFC ek jaise faults nahi hote.
Sabse important professional rule:
PEHLE YE DECIDE KARO KE FAULT DIGITAL SIDE PAR HAI YA RF/ANTENNA SIDE PAR
Master formula:
POWER → CLOCK / RESET → DIGITAL COMMUNICATION → RF PATH → ANTENNA → FUNCTION
1. Wireless Fault ki Main Categories
Customer complaint ko exact category mein divide karo:
1. Wi-Fi Greyed Out
2. Wi-Fi ON Hota Hai but Networks Nahi Milte
3. Wi-Fi Range Bohat Kam
4. Wi-Fi Disconnect Hota Rehta Hai
5. Bluetooth ON Nahi Hota
6. Bluetooth Devices Nahi Milte
7. Wi-Fi + Bluetooth Dono Dead
8. GPS Location Nahi Milti
9. GPS Inaccurate Hai
10. NFC Kaam Nahi Karta
Har symptom ka diagnostic direction different ho sakta hai.
2. Sabse Powerful Difference
Device Available Hi Nahi
Example:
Wi-Fi toggle greyed.
Bluetooth unavailable.
Strong direction:
POWER / RESET / CLOCK / DIGITAL COMMUNICATION
Device Available Hai but Range Weak
Example:
Wi-Fi ON hai.
Router sirf bilkul qareeb nazar aata hai.
Strong direction:
RF PATH / ANTENNA
3. Wi-Fi Architecture
Simplified path:
SoC → DIGITAL BUS → Wi-Fi / BT COMBO IC → RF FRONT-END → ANTENNA
Parallel requirements:
POWER + CLOCK + RESET
4. Combo IC
Modern smartphones mein Wi-Fi aur Bluetooth aksar same:
COMBO IC
mein integrated hote hain.
Isliye Wi-Fi + Bluetooth dono ek saath dead:
Shared IC/power/clock/reset direction strong hoti hai.
5. Wi-Fi Only Dead, Bluetooth Works
Important clue.
Combo IC completely dead hona less likely.
Focus:
Wi-Fi-specific RF path
Firmware/configuration
Antenna path
Wi-Fi-specific internal section
6. Bluetooth Only Dead, Wi-Fi Works
Same logic.
Look for Bluetooth-specific:
RF path
Antenna routing
Software
Control condition
7. Wi-Fi Greyed Out
Phone settings mein Wi-Fi toggle:
Grey
Disabled
Immediately OFF
Potential areas:
Wireless IC power
Reset
Clock
Digital bus
Firmware
8. Wi-Fi Greyed vs Weak Wi-Fi
Never mix these.
Greyed
Digital initialization problem.
Weak
RF/antenna problem stronger.
9. Wi-Fi Power Rails
Wireless IC may require multiple rails:
Core supply
I/O supply
RF supply
Exact names/model-specific.
10. Wireless Power Test State
Some rails only Wi-Fi enable karne par appear kar sakti hain.
Phone idle/off state mein 0V normal ho sakta hai.
11. Wi-Fi Power Missing
Use schematic:
Source
↓
Regulator
↓
Wireless IC.
12. Regulator Diagnosis
VIN → EN → OUT
If VIN missing:
Upstream.
If EN missing:
Control.
If VIN + EN good but output missing:
Regulator/load.
13. Wireless Rail Short
Power removed.
Measure resistance.
Compare known-good.
Do not assume combo IC short immediately.
14. External/Support Components
Wireless rail may also feed:
Filters
Front-end modules
Support circuitry
15. Wireless Reset
Combo IC usually needs reset/release condition.
If reset stuck:
Wi-Fi/Bluetooth unavailable.
16. Wireless Clock
Wireless system may use reference clock.
If missing:
IC may not initialize.
17. Power Good + Reset Good + Clock Missing
Clock source/path direction.
18. Clock Testing
Use safe documented/test point.
Do not unnecessarily probe sensitive oscillator pins.
19. Digital Communication
Wireless IC communicates with SoC.
Possible interfaces:
PCIe
SDIO
UART
Other platform-specific buses
20. PCIe Concept
High-speed digital interface.
Can be used between SoC and wireless subsystem.
21. SDIO
SD-style digital interface.
Some platforms use it for Wi-Fi communication.
22. Bluetooth UART
Bluetooth may use UART or another digital interface depending architecture.
23. High-Speed Bus Warning
PCIe/high-speed lines ko:
Random jumper
Blind probing
Voltage injection
se diagnose mat karo.
24. Digital Bus Evidence
Basic repair mein focus:
Power
Reset
Clock
Software detection
Known-good behavior
before advanced high-speed signal analysis.
25. Wi-Fi MAC Address
If Wi-Fi subsystem properly initializes, system may show Wi-Fi information/MAC.
Missing/invalid info can be a clue.
But software/configuration context also matters.
26. Bluetooth Address
Same concept.
Not a standalone IC diagnosis.
27. Wi-Fi ON but Networks Nahi
Now differentiate:
No networks anywhere
RF receive path.
Some networks but range very weak
Antenna/LNA/filter/contact.
28. Known-Good Router Test
Test close to known-good router.
This removes environmental confusion.
29. Weak Wi-Fi Range Test
Compare same location with another phone.
If fault phone sees:
1–2 networks
and known-good sees:
10+
strong RF issue clue.
30. Wi-Fi Antenna System
Can include:
Antenna flex
Frame antenna
Spring contacts
Coax
RF switch
Filters
LNA/FEM
31. Antenna Contact
Very common after:
Phone drop
Back cover repair
Frame replacement
Previous opening
32. Missing Antenna Screw
Some phones depend on correct grounding/contact through mechanical assembly.
Missing screw/contact can affect RF performance.
33. Coax Cable
Tiny RF coax connects board sections/antennas.
Check:
Proper seating
Damage
Pinched cable
Broken connector
34. Coax Connector Damage
Can cause:
Very weak Wi-Fi
Cellular weakness
GPS issue
depending path.
35. Never Force Coax Connector
Misalignment can permanently damage center contact.
36. RF Filter
Wi-Fi RF signal passes through frequency-specific filters.
37. LNA
LNA:
Low Noise Amplifier
Boosts weak received RF signals.
38. LNA Fault
Can produce:
Very weak receive sensitivity.
39. FEM
Front-End Module may combine:
PA
LNA
Switch
Filters
depending design.
40. RF Components Exact Honay Chahiye
Same-size capacitor/filter ≠ same RF function.
Random replacement mat karo.
41. Wi-Fi PA
Transmit-side amplification.
Fault may result:
Phone sees router but router connection/range/transmit behavior poor.
42. Receive vs Transmit
Important concept.
Receive Fault
Networks not seen / weak.
Transmit Fault
Networks visible but communication/range unstable.
43. Wi-Fi Connects Only Near Router
Strong antenna/RF receive/transmit path clue.
44. Wi-Fi Connects but Internet Slow
Before hardware:
Check:
Router
Internet
Band
Network congestion
Software
45. 2.4 GHz Works, 5 GHz Dead
Very useful.
Band-specific RF path possible.
46. 5 GHz Works, 2.4 GHz Weak
Again band-specific:
Filter
FEM
Antenna
Switch
47. Wi-Fi 6 / 6E / 7 Features
Exact supported bands/features model-specific.
Do not diagnose missing feature before confirming device officially supports it.
48. Bluetooth Architecture
Simplified:
SoC → COMBO IC → RF PATH → ANTENNA
49. Bluetooth Power
Often shared with Wi-Fi combo IC.
If both dead:
Shared power strong suspect.
50. Bluetooth ON but Devices Not Found
Could be:
RF antenna
Bluetooth-specific RF path
Software
Other device issue
51. Bluetooth Range Very Low
Strong RF/antenna clue.
52. Bluetooth Works Only Very Close
Check:
Antenna contact
RF path
Combo IC front-end
53. Bluetooth Audio Cuts
Before motherboard:
Test different earbuds/device.
Check interference.
Then RF path.
54. Wi-Fi + Bluetooth Both Weak
Common antenna/shared RF section possible.
55. Wi-Fi Grey + Bluetooth Grey
Common:
Combo IC power
Reset
Clock
Digital communication
56. Wi-Fi Works + Bluetooth Grey
Do not immediately replace combo IC.
Bluetooth-specific configuration/control can fail.
57. Airplane Mode Test
Use only to compare subsystem behavior.
If toggling airplane mode temporarily restores function:
Software/control initialization possible.
58. Reboot Restores Wireless Temporarily
Could be:
Firmware
Thermal
Intermittent power
Hardware instability
Need repeated evidence.
59. Wi-Fi Dies When Phone Gets Hot
Could be:
Thermal instability
IC solder/board issue
Power rail
But do not random reflow.
60. No Random Wi-Fi IC Reflow
Temporary improvement after heating does not prove correct root cause.
61. GPS / GNSS Introduction
GPS is part of broader:
GNSS
Global Navigation Satellite System.
Can include:
GPS
Galileo
GLONASS
BeiDou
depending phone.
62. GPS Architecture
Simplified:
SATELLITE SIGNAL → ANTENNA → FILTER → LNA → GNSS RECEIVER → SoC/SOFTWARE
63. GPS Signal Bohat Weak Hota Hai
Satellite signal earth par extremely weak hota hai.
Antenna/LNA path quality critical.
64. Indoor GPS Test
Indoor environment mein poor/no GPS lock normal ho sakta hai.
Do not diagnose hardware indoors only.
65. Proper GPS Test
Open outdoor area.
Clear sky.
Known-good comparison.
66. GPS No Lock
Possible:
Antenna
Coax/contact
Filter
LNA
GNSS power
Software
67. GPS Inaccurate
Could be:
Weak satellite reception
Software/maps
Compass calibration
Environmental obstruction
68. GPS vs Compass
Again:
GPS
Position.
Magnetometer
Direction.
69. Maps Arrow Wrong Direction
Could be compass/magnetometer issue while GPS position is correct.
70. GPS Takes Very Long to Lock
Weak RF path possible.
71. GPS Works Outdoors but Not Car/Indoor
May be normal environmental effect.
72. GPS Antenna
Can share frame/contact assembly.
After frame/back replacement:
Check physical contacts.
73. GNSS LNA
Low Noise Amplifier strengthens weak satellite signal before receiver.
74. GNSS LNA Power
Some active RF sections need power.
If missing:
GPS sensitivity can collapse.
75. GPS Receiver
May be integrated in modem/wireless/SoC architecture depending platform.
76. GPS Software Data
Before board repair:
Check location permission/settings.
But if hardware repair context strong, continue electrical diagnosis.
77. NFC Introduction
NFC:
Near Field Communication
Very short-range wireless communication.
Used for:
Contactless functions
Tags
Pairing
Payment systems
depending device/region.
78. NFC Architecture
Simplified:
SoC → NFC CONTROLLER → MATCHING NETWORK → NFC ANTENNA
79. NFC Antenna
Often large coil integrated with:
Back cover
Wireless charging assembly
80. NFC Dead After Back Cover Repair
Strongly inspect:
NFC/wireless charging coil assembly.
Contacts.
Flex.
81. NFC Works Only at Very Specific Angle
Could be:
Antenna alignment
Coil damage
Contact problem
82. NFC Controller Power
If phone doesn't detect NFC subsystem:
Check controller power/reset/control.
83. NFC Antenna Open
Controller may initialize but communication range becomes zero/very poor.
84. NFC Matching Network
RF matching components tune antenna.
Wrong/missing component can kill performance.
85. Random NFC Component Replacement
Avoid.
Exact matching values matter.
86. Wireless Charging + NFC Shared Assembly
On many phones they are physically related.
If both fail after rear repair:
Shared coil/flex/contact strong suspect.
87. NFC Works, Wireless Charging Dead
Common assembly may still be partially functional.
Trace separate paths.
88. Wireless Charging Works, NFC Dead
NFC controller/matching branch may be separate.
89. Wi-Fi after Liquid Damage
Common:
Antenna corrosion
Coax corrosion
Wireless rail leakage
Combo IC area damage
90. Wi-Fi after Drop
First:
Antenna contacts
Coax
Board connectors
before wireless IC.
91. Wi-Fi after Frame Replacement
Very common:
Missing antenna contact/screw/grounding.
92. Bluetooth after Repair
If fault started after opening:
Check:
Flex.
Coax.
Antenna spring.
93. GPS after Back Cover Repair
Antenna contact/assembly.
94. NFC after Battery Replacement
If nearby wireless/NFC flex was disconnected:
Check seating/damage.
95. Wireless Rail Resistance
Power removed.
Measure relevant supply.
Compare known-good board.
96. Very Low Wireless Rail
Could be:
Combo IC
Front-end module
Decoupling capacitor
Other consumer
Need net map.
97. Wireless IC Heating
Heat alone not proof.
Could be:
Active operation
Downstream load
Internal fault
98. Combo IC Completely Cold
Also not proof.
If power rail absent, naturally cold.
99. Digital Detection First
Before RF fault diagnosis:
Does system recognize wireless subsystem?
100. If Wi-Fi Toggle Works
Digital initialization works to significant degree.
Then weak range = RF side stronger.
101. If Wi-Fi Toggle Grey
Do not start antenna repair.
Antenna cannot usually cause Wi-Fi setting to disappear entirely.
102. Bluetooth Similar Rule
Bluetooth toggle works but range weak:
RF.
Toggle unavailable:
Digital/power.
103. GPS Has No Simple Toggle Clue
Use:
Satellite/location behavior
GNSS service detection
Outdoor comparison
RF path inspection
104. NFC Toggle Available but No Tags Detected
Antenna/matching path stronger.
105. NFC Toggle Missing/Subsystem Absent
Power/control/controller.
106. Wi-Fi Signal Measurement
Software RSSI readings can be useful for relative comparison.
But exact dBm values depend environment.
107. Compare Same Router Same Position
Fault phone vs known-good.
This makes test meaningful.
108. Bluetooth Range Comparison
Same earbuds/device.
Same room.
Known-good phone.
109. GPS Comparison
Both phones same outdoor location.
Allow same test conditions.
110. NFC Comparison
Same known-good NFC tag.
Same contact position.
111. Oscilloscope Role
Use for:
Wireless enable
Reset
Power stability
Accessible reference/control clocks
Not actual GHz Wi-Fi/RF carrier measurement.
112. Multimeter Role
Useful for:
Power rails
Resistance
Connector continuity
Antenna contact continuity where circuit supports
Control lines
113. Standard Scope Cannot Fully Analyze RF Carrier
Actual Wi-Fi/Bluetooth/cellular RF requires specialized RF test equipment.
114. RF Spectrum Analyzer
Advanced lab tool used to view RF spectrum.
Not necessary for basic board diagnosis.
115. RF Power Meter / Test Equipment
Advanced transmit testing.
Again shop basic workflow starts with:
Module/antenna/power/control.
116. Never Inject Random Signal into RF Path
RF systems sensitive.
Random signal/voltage can damage front-end.
117. RF Antenna Connector Testing
Do not apply DC blindly.
First know circuit because antenna line can include bias/tuning components.
118. Antenna Tuner
Some smartphones use tuners to optimize antenna for bands/conditions.
119. Antenna Tuner Fault
Can create band/range-specific problems.
120. MIMO
Modern Wi-Fi/cellular can use multiple antennas.
One antenna path failure may reduce performance without total failure.
121. Wi-Fi MIMO Fault
Phone still connects.
But:
Speed poor
Range reduced
One band unstable
122. Common Grounding Issue
RF performance depends on proper chassis/frame grounding.
Missing shields/screws/contacts matter.
123. RF Shield
Shield removal/damage can affect EMI/RF performance.
Restore correctly.
124. Case Study 1 — Wi-Fi Greyed
Wi-Fi and Bluetooth both unavailable.
Shared wireless rail absent.
Regulator VIN present.
Enable absent.
Direction:
Wireless power enable/control.
125. Case Study 2 — Wireless Rail Fault
Wi-Fi + Bluetooth dead.
Power enable present.
Output rail low due abnormal load.
Direction:
Wireless rail consumers.
126. Case Study 3 — Wi-Fi Very Weak
Wi-Fi toggle works.
Router detected only within one meter.
Coax connector partially detached.
Root:
RF antenna path.
127. Case Study 4 — Wi-Fi Weak After Frame Change
Wireless IC initializes normally.
Antenna spring contact missing.
Root:
Physical antenna contact.
128. Case Study 5 — 2.4 GHz Works, 5 GHz Dead
Known-good software/configuration.
Band-specific RF front-end fault evidence.
Direction:
5 GHz RF branch.
129. Case Study 6 — Bluetooth Dead, Wi-Fi Fine
Bluetooth range completely absent.
Wi-Fi normal.
Specific Bluetooth RF path/component investigated.
Lesson:
Combo IC does not mean every fault is common.
130. Case Study 7 — Wi-Fi + Bluetooth Both Grey
Power rails good.
Reset remains low.
Direction:
Wireless reset/control.
131. Case Study 8 — GPS No Lock
Outdoor test.
Known-good phone locks.
Fault phone sees poor/no satellites.
Antenna contact corroded.
Root:
GNSS antenna path.
132. Case Study 9 — GPS Position Correct, Arrow Wrong
GPS works.
Compass direction wrong.
Direction:
Magnetometer/calibration, not GPS receiver.
133. Case Study 10 — GPS Slow after Drop
GNSS power good.
Antenna coax damaged.
Root:
RF receive path.
134. Case Study 11 — NFC Dead After Back Repair
NFC toggle normal.
Tags never detect.
Rear NFC coil flex not connected.
Root:
NFC antenna assembly.
135. Case Study 12 — NFC + Wireless Charging Dead
Both fail after rear assembly replacement.
Shared coil/flex/contact problem found.
Root:
Rear assembly connection.
136. Case Study 13 — Wi-Fi Works Until Phone Hot
Wireless rails stable cold.
Fault repeats with heat.
Physical/reliability evidence required.
Direction:
Thermal/intermittent wireless subsystem.
Do not random reflow.
137. Case Study 14 — Bluetooth Cuts Only with One Earbud
Other Bluetooth devices work normally.
Diagnosis:
Accessory issue, not phone.
138. Case Study 15 — No Networks after Liquid
Wi-Fi initializes.
No networks even beside router.
RF front-end corrosion found.
Direction:
Wi-Fi receive path.
139. Wi-Fi Diagnostic Worksheet
Phone Model: __________
Wi-Fi Toggle: Working / Grey
Wi-Fi MAC Info: __________
Networks Detected: __________
Range: __________
2.4 GHz: __________
5 GHz: __________
Wireless Power Rails: __________
Reset: __________
Clock Evidence: __________
Digital Interface Evidence: __________
Antenna Contacts: __________
Coax: __________
RF Front-End: __________
Known-Good Comparison: __________
Final Direction: __________
140. Bluetooth Worksheet
Bluetooth Toggle: __________
Devices Detected: __________
Range: __________
Wi-Fi Status: __________
Shared Rails: __________
Antenna/Coax: __________
Known-Good Accessory Test: __________
Final Direction: __________
141. GPS/GNSS Worksheet
Outdoor Test: __________
Location Fix: __________
Known-Good Comparison: __________
GPS Power: __________
Antenna Contact: __________
Coax: __________
Filter/LNA: __________
Compass Separate Test: __________
Final Direction: __________
142. NFC Worksheet
NFC Toggle/Detection: __________
Known-Good Tag: __________
Rear Coil/Flex: __________
Contacts: __________
Controller Power: __________
Wireless Charging Status: __________
Final Direction: __________
143. Wi-Fi Decision Tree
Toggle available?
NO ↓
Power.
↓
Reset.
↓
Clock.
↓
Digital communication.
Toggle available?
YES ↓
Networks visible?
NO → RF receive/antenna.
YES ↓
Range weak?
YES → antenna/front-end.
144. Wi-Fi + Bluetooth Decision Tree
Both dead?
↓
Shared power.
↓
Reset.
↓
Clock.
↓
Combo IC/digital bus.
One only dead?
↓
Specific RF/control path.
145. Weak Wi-Fi Decision Tree
Known-good router/location.
↓
Antenna contact.
↓
Coax.
↓
Filter/LNA/FEM.
↓
Combo IC last.
146. GPS Decision Tree
Test outdoors.
↓
Known-good comparison.
↓
Antenna/contact.
↓
Filter/LNA.
↓
GNSS power/control.
147. NFC Decision Tree
Toggle/controller available?
NO → power/control.
YES ↓
Known-good tag detected?
NO ↓
Coil/flex/contact.
↓
Matching network.
148. Wireless Digital-Side Golden Rule
If wireless feature:
SYSTEM MEIN AVAILABLE HI NAHI
then think:
POWER → RESET → CLOCK → DIGITAL BUS
149. Wireless RF-Side Golden Rule
If feature available but:
RANGE WEAK
then think:
RF FRONT-END → COAX → ANTENNA
150. Common Beginner Mistake 1
Wi-Fi greyed = antenna fault.
151. Common Beginner Mistake 2
Weak Wi-Fi = Wi-Fi IC replace.
152. Common Beginner Mistake 3
Wi-Fi + Bluetooth both dead mein shared power ignore karna.
153. Common Beginner Mistake 4
Indoor GPS test se GPS hardware dead bolna.
154. Common Beginner Mistake 5
GPS aur compass ko same samajhna.
155. Common Beginner Mistake 6
NFC dead mein rear coil/flex inspect na karna.
156. Common Beginner Mistake 7
RF component ko same-size random component se replace karna.
157. Common Beginner Mistake 8
Coax connector ko force karna.
158. Common Beginner Mistake 9
Actual RF signal ko normal multimeter/scope se fully diagnose karne ki koshish.
159. Common Beginner Mistake 10
Wireless IC ko random heat/reflow karna.
160. Wi-Fi Golden Rules
1. Greyed Wi-Fi = digital side first.
2. Weak Wi-Fi = RF/antenna side first.
3. Wi-Fi + Bluetooth together dead = shared subsystem check.
4. Power → Reset → Clock → Digital Bus order follow karo.
5. 2.4 GHz aur 5 GHz separate RF branches ho sakte hain.
6. Frame/coax/antenna contacts RF repair ka major part hain.
7. RF components exact specification ke hone chahiye.
8. Known-good same-location comparison useful hai.
9. Random combo-IC reflow diagnosis nahi.
10. Combo IC ko last mein conclude karo after prerequisites.
161. Bluetooth Golden Rules
1. Bluetooth range weak = antenna/RF check.
2. Bluetooth + Wi-Fi both unavailable = common power/control.
3. Known-good Bluetooth accessory se test karo.
4. One accessory issue ko phone fault mat samjho.
5. Wi-Fi functioning combo IC ke health ka useful clue hai.
162. GPS Golden Rules
1. GPS proper outdoor environment mein test karo.
2. GPS position aur compass direction separate systems hain.
3. Weak/no satellite lock = antenna/LNA/filter first.
4. Back/frame repair ke baad antenna contacts check karo.
5. GNSS receiver IC ko last-stage suspect rakho.
163. NFC Golden Rules
1. NFC antenna rear assembly mein ho sakti hai.
2. Back-cover repair ke baad coil/flex/contact first check karo.
3. NFC matching components frequency-specific hain.
4. NFC + wireless charging together dead = shared assembly clue.
5. Security/payment functionality ko bypass nahi karna; legitimate original function restore karna hai.
164. Part 27 Quick Revision
Combo IC
Wi-Fi + Bluetooth integrated wireless IC.
RF Front-End
Filters, PA, LNA, switches etc.
LNA
Low Noise Amplifier.
FEM
Front-End Module.
Coax
Shielded RF connection cable.
GNSS
Satellite navigation system family.
NFC
Near Field Communication.
MIMO
Multiple antenna paths for better wireless performance.
Digital-Side Fault
Power/reset/clock/bus initialization problem.
RF-Side Fault
Antenna/filter/amplifier/radio path problem.
165. Part 27 ka Sabse Important Lesson
Wireless repair mein sabse pehla sawal:
FEATURE AVAILABLE HAI YA AVAILABLE HI NAHI?
Agar Wi-Fi toggle grey hai:
POWER → RESET → CLOCK → DIGITAL BUS
Agar Wi-Fi ON hai lekin sirf router ke bilkul qareeb chalti hai:
RF PATH → COAX → ANTENNA
Agar Wi-Fi + Bluetooth dono dead:
SHARED POWER / CLOCK / RESET / COMBO SYSTEM
Agar GPS no lock:
Pehle outdoor known-good comparison aur antenna receive path.
Agar NFC dead after rear repair:
Pehle rear coil/flex/contact.
Professional wireless diagnosis ka golden formula:
DIGITAL SIDE KO RF SIDE SE ALAG KARO
Aur phir:
POWER → CLOCK/RESET → DIGITAL COMMUNICATION → RF PATH → ANTENNA → FUNCTION
Mobile Repair Course — Part 27 Complete
Next — Mobile Part 28: Smartphone Cellular No Service + SIM + Baseband + RF Advanced Diagnostic Workflow
Part 28 mein hum real shop-level workflow mein cover karenge:
No SIM
SIM detected but No Service
Searching
Emergency Calls Only
Weak signal
Signal drops
One SIM slot dead
IMEI/baseband status clues
Modem power/reset
RF transceiver
PA/LNA
Antenna switch
Band-specific faults
4G/5G troubleshooting
Call/data-triggered restart
Antenna/coax/contact faults
Master formula:
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