70 Professional Questions with Complete Answers
Note: Agar student is chapter ko samajh gaya, to woh Dell, HP, Lenovo, ASUS aur Acer ki 80% power problems diagnose kar sakta hai.
Basic Knowledge
Q1. Voltage Regulator ka Reference Designator kya hota hai?
Answer:
Normally U
Example:
- U101
- PU301
- U500
Q2. Voltage Regulator kya hota hai?
Answer:
Voltage Regulator ek IC hoti hai jo input voltage ko stable aur required output voltage mein convert karti hai.
Q3. Voltage Regulator ka main kaam kya hota hai?
Answer:
- Stable Voltage dena
- Voltage Convert karna
- Over Voltage se protection
- Sensitive ICs ko safe supply dena
Q4. Laptop motherboard mein Voltage Regulator kahan use hota hai?
Answer:
- CPU
- RAM
- PCH
- BIOS
- KBC
- SSD
- USB
- Display
- Audio
Q5. Voltage Regulator kitne types ki hoti hai?
Answer:
- LDO (Linear Regulator)
- Buck Converter
- Boost Converter
- Buck-Boost Converter
LDO (Low Dropout Regulator)
Q6. LDO ki Full Form kya hai?
Answer:
Low Dropout Regulator
Q7. LDO ka kaam kya hota hai?
Answer:
Higher voltage ko low stable voltage mein convert karna.
Example:
5V → 3.3V
Q8. LDO aur Buck Converter mein kya difference hai?
Answer:
LDO
- Simple
- Noise kam
- Heat zyada
Buck Converter
- Efficient
- Heat kam
- High Current handle karta hai
Q9. LDO kis type ki supply ke liye best hota hai?
Answer:
Low Current Circuits
Q10. Laptop mein LDO kin ICs ko supply deta hai?
Answer:
- BIOS
- KBC
- RTC
- Audio
- Sensors
Buck Converter
Q11. Buck Converter kya hota hai?
Answer:
DC Voltage ko kam karta hai.
Example:
19V → 5V
19V → 3.3V
Q12. Buck Converter ke main components kya hote hain?
Answer:
- PWM IC
- MOSFET
- Coil
- Capacitor
- Feedback Resistors
Q13. Buck Converter ki efficiency kitni hoti hai?
Answer:
Aam tor par 85%–95%.
Q14. CPU Voltage kis converter se banti hai?
Answer:
Buck Converter
Q15. RAM Voltage kis converter se banti hai?
Answer:
Buck Converter
Boost Converter
Q16. Boost Converter kya karta hai?
Answer:
Voltage ko increase karta hai.
Example:
5V → 12V
Q17. Laptop mein Boost Converter kahan use hota hai?
Answer:
- LCD Backlight
- LED Driver
- Kuch Display Circuits
Q18. Boost Converter ke main parts kya hote hain?
Answer:
- PWM IC
- MOSFET
- Coil
- Diode
- Capacitor
Q19. Boost Converter ki output input se kaisi hoti hai?
Answer:
Input se zyada.
Q20. Boost Converter fail ho jaye to?
Answer:
Backlight ya high-voltage circuit kaam nahi karega.
PWM Controller
Q21. PWM ki Full Form kya hai?
Answer:
Pulse Width Modulation
Q22. PWM IC ka kaam kya hota hai?
Answer:
MOSFET ko ON/OFF karke required voltage banana.
Q23. PWM IC ke bina Buck Converter chalega?
Answer:
Nahi.
Q24. PWM IC ko sab se pehle kya chahiye hota hai?
Answer:
VIN Supply
Q25. PWM IC ka Enable pin kis liye hota hai?
Answer:
Converter ko ON karne ke liye.
Voltage Rails
Q26. 3.3V Rail kis liye hoti hai?
Answer:
BIOS
KBC
IO Devices
Q27. 5V Rail kis liye hoti hai?
Answer:
USB
SSD
HDD
Logic Circuits
Q28. CPU VCORE kya hoti hai?
Answer:
CPU ki main working voltage.
Q29. RAM Voltage kitni hoti hai?
Answer:
DDR Type par depend karti hai.
Example:
DDR4 ≈ 1.2V
DDR5 ≈ 1.1V
Q30. RTC Voltage kitni hoti hai?
Answer:
Lagbhag 3V
Practical Questions
Q31. 19V aa rahi hai, 3.3V nahi aa rahi. Sab se pehle kya check karoge?
Answer:
- Input MOSFET
- PWM IC VIN
- Enable Signal
Q32. PWM VIN hai lekin output nahi hai.
Answer:
Enable Signal ya PWM IC check karo.
Q33. Enable hai lekin switching nahi ho rahi.
Answer:
PWM IC ya MOSFET fault ho sakta hai.
Q34. Coil par 0V hai.
Answer:
PWM Circuit troubleshoot karo.
Q35. Coil garam ho rahi hai.
Answer:
Output Short ya MOSFET fault.
Q36. Output capacitor short hai.
Answer:
PWM protection mode mein ja sakta hai.
Q37. 3.3V rail short hai.
Answer:
Resistance to Ground measure karo.
Injection Method use karo.
Q38. Injection Method kya hai?
Answer:
Limited Voltage aur Current inject karke shorted component locate karna.
Q39. Buck Converter ka output unstable hai.
Answer:
Capacitor ya Feedback Circuit check karo.
Q40. Feedback Resistor ka kya kaam hai?
Answer:
Output Voltage regulate karna.
Shop Level Questions
Q41. Schematic mein Buck Converter kaise identify karte ho?
Answer:
PWM IC ke saath:
- Coil
- MOSFET
- Capacitors
Ek group mein nazar aayenge.
Q42. Boardview mein PWM IC kaise search karte ho?
Answer:
Reference U ya PU se.
Q43. Power Rail ka sab se aasaan test point kya hota hai?
Answer:
Coil
Q44. Coil par voltage milne ka kya matlab?
Answer:
Rail generate ho rahi hai.
Q45. Coil par voltage nahi hai.
Answer:
PWM ya Enable missing.
Q46. PWM IC garam hai.
Answer:
Short ya internal fault.
Q47. MOSFET garam hai.
Answer:
Short Load ya PWM issue.
Q48. Input 19V hai, Output 0V.
Answer:
PWM Enable, Gate Signal aur MOSFET check karo.
Q49. Input 19V hi nahi hai.
Answer:
DC Jack
Fuse
TVS
Input MOSFET
Q50. 3.3V hai, 5V nahi.
Answer:
5V Buck Converter troubleshoot karo.
Advanced Questions
Q51. Power Good Signal (PGOOD) kya hota hai?
Answer:
Signal jo batata hai ke output voltage stable hai.
Q52. VR_ON Signal kya hota hai?
Answer:
CPU VRM ko ON karne ka Enable Signal.
Q53. SLP_S5# Signal kis liye hota hai?
Answer:
Sleep State se Power Sequence control karta hai.
Q54. SLP_S3# Signal kis liye hota hai?
Answer:
Sleep se Resume Power ko control karta hai.
Q55. RSMRST# Signal kya hai?
Answer:
Resume Reset Signal jo PCH aur KBC ke startup sequence ka important hissa hota hai.
Q56. PLTRST# kya hai?
Answer:
Platform Reset Signal.
Q57. ALL_SYS_PWRGD kya hota hai?
Answer:
Sab major rails stable hone ki indication.
Q58. EC_ON kya hota hai?
Answer:
Embedded Controller ka enable signal.
Q59. Schematic troubleshoot karte waqt sab se pehle kya dekhna chahiye?
Answer:
Power Flow
Input se Output tak.
Q60. Technician ki sab se badi galti kya hoti hai?
Answer:
Voltage measure kiye baghair IC replace kar dena.
Interview Questions
Q61. 19V hai. 3.3V aur 5V dono missing hain. Sab se pehle kya check karoge?
Answer:
Always-on PWM IC, uska VIN, EN aur MOSFET.
Q62. 3.3V hai lekin Power Button kaam nahi kar raha.
Answer:
KBC aur Power Button Circuit check karo.
Q63. KBC ko 3.3V nahi mil rahi.
Answer:
LDO ya 3.3V Rail troubleshoot karo.
Q64. CPU VCORE nahi ban rahi.
Answer:
VR_ON, PWM, MOSFET aur CPU VRM section check karo.
Q65. Laptop Auto ON ho raha hai.
Answer:
Power Button Circuit ya KBC issue ho sakta hai.
Q66. Laptop 1 second baad OFF ho jata hai.
Answer:
Power Sequence fail ho rahi hai.
Q67. Laptop Current 0.02A par ruk gaya.
Answer:
Standby State mein atka hua ho sakta hai.
Q68. Laptop 0.25A par ruk gaya.
Answer:
Power Sequence ke agle stage (BIOS, Clock, Reset ya CPU initialization) ko investigate karo.
Q69. Professional Golden Rule
Question:
Power troubleshooting ka sab se important rule kya hai?
Answer:
"Power ko hamesha sequence ke mutabiq trace karo. Beech se troubleshooting shuru mat karo."
Q70. Shop Final Practical Question
Question:
Dell Laptop dead hai. Adapter lagane par 19V aa rahi hai. Student ko complete troubleshooting sequence likhna hai.
Answer:
- DC Jack par 19V verify karo.
- Input Fuse check karo.
- TVS Diode short check karo.
- Input MOSFET (Drain, Source, Gate) voltages measure karo.
- Charger IC ka VIN, ACDET, ACOK, REGN aur CMSRC check karo.
- 3.3V ALW aur 5V ALW Buck Converter verify karo.
- PWM IC ka VIN aur EN check karo.
- Coils par voltage aur resistance to ground measure karo.
- KBC ko 3.3V aur RTC supply mil rahi hai ya nahi verify karo.
- Power Button signal check karo.
- BIOS supply aur SPI communication verify karo.
- Clock Signals (RTC aur main clock) check karo.
- Reset Signals (RSMRST#, PLTRST#) verify karo.
- VR_ON aane ke baad CPU VCORE generate ho rahi hai ya nahi check karo.
- Har step par schematic aur boardview follow karke fault isolate karo.
🔥 Agla Chapter (Chapter 10)
Ab se course professional level mein enter hoga.
Chapter 10 – BIOS IC (SPI Flash Memory) mein hum 80–100 professional questions cover karenge, jisme:
- BIOS IC ki internal working
- SPI Pins (CS#, CLK, DO, DI, WP#, HOLD#)
- 1.8V vs 3.3V BIOS
- BIOS programming
- BIOS corruption
- EC BIOS vs Main BIOS
- Intel ME
- Dell Service Tag
- Real shop troubleshooting
- Schematic aur boardview se BIOS diagnosis
Yeh chapter kisi bhi motherboard repair technician ke liye sab se important chapters mein se ek hoga.
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