Redmi 12 5G Dead Phone Fix: CPU Level Repair Ka Full Process (Step-by-Step Guide)
Hello dosto swagat apka hamare es article me, aaj ham aapko batayenge ki kaise dead mobile aaye to esko step by step kaise check kare.
Aaj hmare pas 1 Redmi 12 5G ka phone aaya jo puri tarah se band hai. Jab bhi dead aapke pas aaye to sabse pahle aapko coustmer se question karna hai ki uska phone kis karan band hau hai. Achanak se band hua hai, ya phone gir gaya tha jameen par ya pani me to nahi gir gaya tha pahle coustmer se confirm kar lena ki kis wajah se uska phone band hau hai.
Maine apne coustmer se pucha to usne kaha ki phone achanak se band hua hai kahi phone gira nahi hai, usne ye bhi bola mere yha aane se pahle o kisi shop par ja kar phone dikhaya tha lekin ban nahi paya.
🔍 4️⃣ Problem ko classify karo (unique part)
- Battery dead / power IC issue
- Software crash
- Water damage
- CPU soldering issue (serious case)
🔧 Step 1: Basic check
Redmi 12 5G phone ko 6 port charger me lagaya to charger koi bhi ampear consume nahi kiya. Phone ko separator machine par 100°C par set karke phone ko 2 minute tak heat kiya uske baad back panel ko savdhani se remove kiya. Uske bad pure screw ko bahar kar phone midel ko bhi remove kiya.
Phone ko open karne ke baad charge laga kar check kiya koi part over heat to nahi ho raha, agar koi component full short rahta hai to kabhi kabhi easly pata chal jata hai. Lekin es case me koi bhi part heat nahi ho raha tha.
🔧 Step 2: GR & Voltage Check
Shunshine DT-17N multimeter se jab battery connector par GR check kiya to VBAT (Reverse Bias – 0.456 & Forward Bias – 1.200+), Therm (0.856), ID (0.900), GND (0.000) aaya ye condition sahi mana jata hai. Battery ke patte par jab voltage kiya 3.8V bataya eska matlab battery bhi hamara charge hai.
Ye sab check karne ke baad ab ham motherbaord par voltage karenge.
Sabse pahle maine uske battery ka voltage check kiya to 4V volt bataya jo ki battery charge thi, battery 3.7V se upar charge hone chahiye 1 phone ko proper on hone ke liye. Uske bad charge laga kar VBUS(Charhing voltage check kiya jo sub board se main board tak main se aata hai) voltage check kiya to main board me VBUS 5V ban raha hai, lekin battery connector par koi voltage nahi ban raha.
Jab hamne VBUS voltage check kar liya uske baad VPH voltge check karna hai, VPH voltage aap do jagah se asani se check kar sakte hai,
- Charging IC ke pas VPH ka coil laga hota hai
- Power IC ke pas small size ke capacitor lage hote hai ( Jo VPH coil se power ic ke pas aate hai)
Aap dono se kahi se bhi check kar sakte hai, lekin mere hisab se power ick e pas check karne jyada sahi rahta hai kyuki VPH voltage check karne ke bad buck voltage check karne hota hai jom power ic se buck coil me aata hai, Jabke buck voltage aap charging ic ke pas nahi check kar sakte hai. Es tarah kam karne se aapko motherboard ke upar ke shield lage hote hai jisse use kam nikalna padta hai, aur board par kam heat padta hai.
Uske bad ham power ic ka location check karenge ki board me kis jagah laga hai, agar aapko pata hai ki kis jagah hai to aap us shield ko remove kariye, agar nahi pata hai to aap borneo ki madat se power ic ka location pata kar sakte hai. Technician ko sabse jyada pareshan karne wala kam hai, shield ko bahar kaise kare safe way me, jyada tar log cutter ka use karte hai kabhi kabhi safe nikal jata hai nahi to board ka print nikal jata hai kayi bar to sahi phone bhi kharab ho jata hai.
Aapko kya karna hai low teprature ka PPD (138) lena hai jis shield ko hatana hai uske charo taraf ppd laga dena hai aur flux laga kar pale shield ko resold kar lena hai, esse kya hota hai jo company ka ppd hota hai o low tempruture me convert ho jata hai. Jisse SMD par 300 ya 320 heat rakh kar heat karenge to shield aasani se bahar ho jata hai.
Sheild hatane ke baad power ic ke pas me jitne bhi capacitor lage hote, un par voltage check karna hai 3.2-4.2V tak agar ban raha hai to charhing ic work kar raha hai. Maine Redmi 12 5G ke es phone me check kiya to VPH voltage ban raha tha. VPH voltage ke bad hame buck voltage check karna hota hai, (Buck voltage 0.7, 0.8 hota hai), maine es phone me buck coil par voltage check to buck voltage ban raha tha.
Eske bad hame lower LDO 1.2V, higher LDO 2.0V check karna hota hai, maine jab es phone ko check kiya to LDO voltage ban raha tha.
Aagar sab voltage ban raha aur phone on nahi ho raha to ham softwere ki taraf jayenge.
🔧 Step 3: Software check
Ham port check krenge ki phone port bana raha hai ki nahi agar port bana raha hai to ese flash karke dekhna padega, Lekin port nahi banaya to doubt haam CPU ic karenge. Mera jo phone hai Redmi 12 5G jab eska port maine check kiya to ye port bana raha tha. Uske baad latest version ka maine flash file downlad kiya, aur flash karne ka try kiya to ye “CPU not found in database” ka error de diya
Ab ye error dekhane ke bad to bate samajh aati hai ya ye UFS se problem hoga ya CPU se. CPU not found ka error tha to maine pahle CPU karne ke bare me socha.
🔧 Step 4: CPU level repair
SMD ka heat 370 par rakh kar aur air 70 par rakh kar thodi der tak heat karne ke bad maine bahut hi aaram se CPU se ko uthaya. Phir board ko desolder wire aur flus ki help se board par lage ranga ko achche se clean kiya. Uske baad CPU ko bhi clean kiya aur 183 PPD se CPU ko rabaal kiya.
Uske baad board par flux laga kar CPU ko set kiya aur phir SMD heat 370 aur air 70 par rakh kar heat kiya board ko thodi der tak thanda hone diya.
Phir motherboard ko phone me set kar ke on kiya, Moble mera Redmi 12 5G complete on ho gaya.
Ab samajhane wali baat ye hai ki Redmi 12 5G ke kisi bhi phone ko same process se on nahi kar sakte hai es ka jo codition tha agar same raha to on hoga nahi to phone ka problem kya pura step by step trace karenge uske hisab se repair karenge.