Charging Section Repair: VBUS, VPH, VBAT & BSI Line Tracing | Lesson 31

Team Tekno World ke free mobile repairing course mein aapka swagat hai! Main hoon Rakesh Chauhan, aur yeh humara Lesson 31 hai.

Aaj se hum Week 6 (Circuit & Component Level Repair) ki shuruat kar rahe hain.

Ab tak humne parts badalna (Folder, Mic, Speaker) seekha. Woh “Labour Work” tha. Aaj se hum “Smart Work” yaani Circuit Tracing seekhenge. jisme Charging Section Repair ke baare me seekhenge

Charging Section Repair

Aksar naye technicians ke paas jab charging fault aata hai, wo seedha Jack badal dete hain, fir Battery badalte hain, aur jab kaam nahi banta toh phone wapas kar dete hain.

Wajah? Unhe VBUS, VPH aur BSI ka farak nahi pata. Aaj hum electricity ka rasta (Path) trace karenge.

Step 1: Diagnostic Start (Bina Phone Khole)

Phone kholne se pehle, usey USB Ampere Tester (6-Port Charger) mein lagayein. Reading aapko bohot kuch bata degi:

• 0.00 Amp: Rasta poori tarah band hai (Jack ya Patta kharab).
• 0.60 Amp: Slow Charging (Data lines connect nahi hain).
• 1.60 Amp – 2.0 Amp: Fast Charging (Circuit OK hai).
• Red Blink / Cut-off: Board mein Shorting hai.

Step 2: VBUS (The Entry Gate – 5V)

Jab aap charger lagate hain, toh current sabse pehle VBUS (Voltage Bus) line par aata hai.

• Source: Charging Jack (Pin 1) se lekar Charging IC tak.
• Voltage: 5.0V se 5.2V.
• Trace Kaise Karein?
  1. Phone kholein aur charger lagayein.
  2. Charging patte ke connector par ya Main Board ke Test Point (TP) par 5V check karein.
  3. Scenario:
     • Agar Jack par 5V hai par Board par nahi = Charging Flex (Patta) kharab hai.
     • Agar Board par 5V aa raha hai par Charging IC tak nahi pahunch raha = Raste mein lagi OVP IC (Over Voltage Protection) fuse ho gayi hai.

Step 3: VPH / VSYS (The Power Plant – 3.7V)

Yeh mobile repairing ka sabse bada concept hai. Purane phones mein charger ka current seedha battery mein jaata tha. Lekin naye Android phones (4G/5G) mein Charging IC (DC-to-DC Converter) pehle VPH Power banati hai.

• Kya hai VPH? Yeh poore phone ki “Jeevan Rekha” (Main Supply) hai. Yeh Network, Audio, CPU, aur Power IC ko chalati hai.
• Pehchan: Charging IC ke bilkul paas ek badi Grey/Black Coil lagi hoti hai.
• Testing:
  1. Charger lagayein (Bina Battery ke).
  2. Is Coil par voltage check karein.
  3. Reading: 3.7V se 4.2V milna chahiye.
• Fault: Agar VBUS (5V) aa raha hai par VPH (3.7V) nahi ban raha, toh aapki Charging IC (PMI/BQ) kharab hai. Phone Dead bhi ho sakta hai kyunki VPH nahi banegi toh phone ON nahi hoga.

Step 4: VBAT (The Final Destination)

VPH banne ke baad, Charging IC current ko switch karke Battery Connector par bhejti hai. Isey VBAT kehte hain.

• Testing:
  1. Battery nikaal lein aur charger laga rehne dein.
  2. Battery connector ki Positive (+) pin par check karein.
  3. Reading: Yahan voltage sthir (stable) nahi rahega. Yeh 3.6V se 4.2V ke beech naachega (fluctuate karega). Yeh fluctuation batata hai ki IC battery dhoondh rahi hai.
• Fault: Agar VPH OK hai, par VBAT par 0V hai, toh Charging IC aur Battery Connector ke beech laga Current Sensing Resistor open ho gaya hai.

Step 5: BSI / ID Line (The Silent Killer)

Ab aate hain us pin par jise 90% log ignore karte hain. Battery connector ki beech wali pin: BSI (Battery Status Indicator) ya ID.

• Kaam: Yeh CPU ko batati hai: “Battery lag gayi hai, uska temperature kya hai aur wo kitni charge hai.”
• Fault Symptoms:
  1. Restart on Logo: Phone MI/Samsung logo par aakar baar-baar band-chalu hoga.
  2. Battery Error: “Temperature too high/low” ya “Invalid Battery”.
  3. Fake Charging: Charge ka nishan aayega par % nahi badhega.
• Testing (Cold Test):
  • Battery nikaal kar connector ki beech wali pins par Diode Mode (GR Value) check karein.
  • Reading: 300 se 800 ke beech aani chahiye. Agar ‘OL’ (1) hai, toh rasta toota hai. Schematic se Resistor dhoondhein aur badlein.

Summary Checklist (Tracing Flow)

Ek professional technician aise check karta hai:

1. Jack/Test Point: 5V OK? (Agar nahi = Jack/Flex issue).
2. VPH Coil: 3.7V OK? (Agar nahi = Charging IC/OVP issue).
3. Battery Connector (+): Fluctuating Voltage OK? (Agar nahi = Track open).
4. BSI/ID Pin: GR Value OK? (Agar nahi = Restart/Error problem).

💡 Aaj Ka Aapka Task – Lesson 31 (Comments & Forum)

1. Practical: Apne multimeter se kisi bhi chalu phone (Realme/Redmi) mein Charging IC ke paas wali badi coil par VPH Voltage check karein.
2. Comment (नीचे): Kya aapne kabhi dekha hai ki Battery connector par carbon aane se phone Restart hota hai? Apna experience share karein.
3. Forum: Agar aapko Charging IC (jaise BQ25601 ya PMI632) ki pinout chahiye, toh board ka model Forum (forum.teamtw.in) par maangein.

Agla Lesson: Circuit trace karna aa gaya? Ab hum haath ganda karenge! Agla Lesson hai: “Lesson 32: Charging Jack Replacement (Type-C & Micro USB) Professional Way” jisme hum seekhenge ki Jack kaise badlein bina Mic jalaye.