Says: "Screen phat gaya" / "Screen toot gaya"

What it is: cracked glass, or display + touch dead. Two repair levels: (a) full combo/LCD+frame replacement, (b) glass-only refurbishment (later skill with OCA machine).

Diagnosis: Does the phone work otherwise? Does touch respond? Lines or black patches = display panel dead, not just glass. Test with a flashlight: image visible under light = panel alive, only glass broken.

Fix: 1) Heat rear edges 80-100°C · 2) open per model (suction + picks) · 3) disconnect battery FIRST · 4) remove display screws/flex · 5) TEST the new display connected loosely BEFORE gluing · 6) then fit, adhesive, close.

Gotchas: fingerprint-under-display phones (calibration needed on some) · glued batteries under the display on some models · original vs copy panels (test brightness/fingerprint before selling to customer) · iPhone: True Tone (programmer later).

Price guide: <20K phone Rs.300-500 labor · 20-50K Rs.500-1000 · iPhone Rs.1000-2000 (panel extra).

Says: "Battery khatam ho jata hai" / "Battery kharab hai"

Diagnosis: swollen battery (back lifting!), drains fast, phone dies at 20-30%, gets hot. Check: battery health in settings (some brands), voltage with multimeter (<3.4V resting = weak), age 2+ years = replace anyway.

Fix: open → battery connector off → remove old battery (glued: isopropyl under the battery, pull tabs - NEVER metal prying on a lithium battery, NEVER puncture) → new battery in → connector → test charge percentage movement before closing.

Gotchas: swollen battery = handle like a bomb, keep away from heat, do not test with high current · some models (iPhone, many Samsungs) have stretch-glue requiring IPA soak · always note the battery model code.

Price guide: Rs.200-400 labor + battery Rs.500-1500 by model.

Says: "Charging nahi lagta" / "Charging loose hai" / "Charge hote hote ruk jata hai"

Diagnosis (in order): 1) lint in port - shine light, clean with brush + IPA (fixes 40% of cases, free!) · 2) wiggle test with known-good cable - movement = broken solder joints or worn port · 3) multimeter 5V at port VBUS pin with charger in - 5V present but no charge = board-side · 4) cable charger test with USB-C tester · 5) slow charging only = charger negotiation / dirty contacts / battery aging.

Fix: lint cleaning first (free!) → if loose: reflow port joints with flux (soldering iron, 330-350°C, drag pins) → if pins worn/broken: replace port. Port types: (a) separate flex with port - cheapest, (b) port on main board - hot air removal + solder new, (c) Type-C mid-frame assemblies on newer models.

Price guide: cleaning Rs.50-100 · reflow Rs.200-300 · port replace Rs.300-500 + part.

Says: "Charge ho hi nahi raha" even with new cable

The ladder (bottom to top): charger → cable → port → fuse/line to board → charging IC → battery connector → battery → software.

1. Charger: USB-C tester in line - is it delivering 5V (and 9V when asked)? Try another charger.
2. Cable: swap; frayed cables are 50% of the world's charging problems.
3. Port: clean, wiggle test, VBUS multimeter check (5V present?).
4. Fuse + protection: continuity the fuse near the port; check the protection diode (diode mode).
5. Charging IC: gets hot with charger connected = charging IC dead → replace (hot air 350-370°C).
6. Battery: voltage <3.0V = battery asleep → boost/activate with PSU at 3.7-3.8V low current; battery >4.2V but phone says 0% = fuel gauge/software issue.
7. Software: battery calibration, safe mode test, firmware (flashing resets battery stats).

USB-C tester data is your proof to the customer: "your charger gives 5V/0.8A - that's why it's slow" - customers trust numbers.

Says: "Pani me gir gaya" / "Roo me gir gaya"

What water actually does: minerals stay after drying, grow dendrites/corrosion between tracks, cause shorts over days. The phone dying NOW is the start, not the end.

The protocol:

1. Do NOT charge it or test-charging it. Powering a wet board grows corrosion. Tell the customer this - it's why "drying in rice" fails.
2. Full teardown - everything out, back covers, shields.
3. Visual under scope: white/green corrosion, water marks on the LCD sticker.
4. Clean: IPA 99% + soft brush everywhere (ultrasonic when bought: 40kHz, 5-10 min in PCB-safe solution).
5. Dry: hot air 80-100°C, high airflow, 5-10 minutes, everything.
6. Inspect under microscope: reflow any corrosion-eaten joints.
7. Reassemble minus battery, power via PSU 4.0V/0.5A - read current before installing the old battery.
8. Then battery, then full function test: charging, touch, cameras, speaker, mic, SIM, WiFi.

Price guide: basic cleaning Rs.300-500 · full treatment + reflow Rs.500-1000 · if the display is dead too, quote separately (water kills displays often).

Says: "Phone on hi nahi ho raha"

Decision tree (see also Section 4.2):

1. Tried known-good charger 30+ min? (Deep-discharge mimics death.)
2. Force restart for the brand: Vol-+Power 10s (most), Power+Vol-up (some Samsungs), etc.
3. Battery voltage - swap or measure. <3.0V: boost first.
4. Open: visual inspection - burn marks, missing components, corrosion, water sticker triggered?
5. PSU test (the pro step): 4.0V/0.5A on battery connector:
   • 0.000A → input path dead: check fuse, charging line, port
   • Steady 0.01-0.03A → press power: no change = power button circuit or PMIC; change = read the pattern
   • Instant max → SHORT → short-killer + freeze spray → find and remove the culprit → retest
   • Steps climbing → it's booting! Problem is display or software - go to 2.7/2.15
6. Power button line: check the button, its flex, and the signal on the board.
7. PMIC hot = replace PMIC (advanced - after schematic skills).

Price guide: diagnosis Rs.100-200 (adjusted into repair) · short repair Rs.500-1000 · depends what dies.

Diagnosis:

1. Prove the phone is alive: call it - rings? Does the flashlight toggle? Fingerprint unlock?
2. Flashlight test: shine at the screen at an angle - if the image is visible faintly = backlight dead (boost circuit), the panel itself is fine.
3. Reseat the display connector (half of these are just bad seating).
4. Test with a known-good display connected loosely.
5. If the new display also dark: check the display rails on the board (VCI ~3.3V, AVDD ~5.5-6V) - missing rail = display PMIC on the board.
6. Backlight dead: check the backlight fuse, coil, boost IC on the board.

Price guide: reseat Rs.100-200 · display replace as 2.1 · backlight repair Rs.500-800.

Diagnosis:

1. Ghost touches? (self-typing = moisture, screen pressure, or touch IC - note pattern)
2. Whole screen dead to touch vs. dead zones? Dead zones = broken flex or damaged digitizer area.
3. Test with a known-good display+touch combo (connected, not glued).
4. New combo also dead = touch IC/line on board (water damage is common here).
5. After a screen replacement, touch dead = wrong panel type or connector seated wrong, or firmware (some models need touch calibration).

Diagnosis:

1. Toggle airplane mode; check SIM in another phone; another SIM in this phone.
2. Check IMEI present: dial *#06# - no IMEI = NV/baseband issue after flashing (repair: re-flash full firmware, restore NV backup - UMT can read/write NV on supported chips).
3. *#*#4636#*#* - check radio state; "airplane" stuck = software.
4. Hardware: antenna contacts, antenna switch/module, RF front-end after a drop. Water = corrosion on RF lines.
5. Voltage on the SIM rails when SIM inserted (1.8V/3V on the SIM pads).
6. Baseband CPU power and clocks = advanced (schematic level).

Gotcha: "no service" after a software flash = wrong firmware region or NV corruption - flashing the correct full firmware fixes most. Never promise IMEI repair on stolen devices - policy.

Diagnosis:

1. Isolate: speaker (ringer), earpiece, mic, headphone jack, Bluetooth - which one?
2. Speaker: multimeter resistance on the speaker pads - 8/16/32Ω = good, OL = dead. Also dirty mesh (clean with brush + IPA).
3. Earpiece same test.
4. Mic: bias test (~2V on mic pin in a call), test voice recorder.
5. Water in the mesh = common after rain; IPA + ultrasonic bath (speaker module out).
6. Software: safe mode test (3rd party app muting), reset sound settings.
7. Board-level: audio IC / codec after water - reflow or replace.

Multimeter the motor: 10-30Ω. Check the vibration pad voltage when a test vibration runs. Motor replacement is a 10-minute job; water-corroded pads = clean/reflow.

Diagnosis:

1. Software first: clear camera app data, safe mode test (a rogue app holds the camera).
2. Blur only: clean the lens, check for a cracked lens glass (outer glass replacement).
3. Black screen in camera app only = camera module or its flex; reconnect/reseat; swap the module.
4. After a drop: connector damage; after water: corrosion on the connector.
5. Board-level: camera power rails (VCAM ~2.8V) missing = PMIC/cam power line (schematic level).

Tray bent/ejector broken = mechanical. SIM not read with a good SIM = SIM reader pins (inspect under scope - bent pins common after wrong-size SIM forcing), corrosion, or SIM power rails. Gentle pin realignment with a needle under the microscope.

Diagnosis:

1. Software: check battery usage stats - a runaway app is 60% of "heat" cases; safe mode; uninstall recent apps.
2. Hotspot/GPS/camera long use is normal heat - explain to the customer.
3. Hot in one spot = hardware: charging IC area hot while charging (charging IC), PMIC area (load issue).
4. Heat while idle = something's always awake (software) or a partial short (PSU current read reveals it).
5. Heat + battery drain + dead phone history = water damage corrosion acting up.

Ladder:

1. Storage full? (Check - a full storage mimics a virus.)
2. Safe mode: fine in safe mode = a bad app - uninstall recently installed ones.
3. Cache wipe via recovery; factory reset (warn: data!).
4. Bootloop (logo bounce): try recovery wipe; then full firmware flash (SP Flash Tool / Mi Flash / Odin per chip) - Week 11 skill.
5. After flash, no network: see 2.9 NV/IMEI note.

Data rule: always ask and note "data will be erased" - get a YES before flashing. Offer backup first when possible.

Price guide: software fix Rs.200-300 · flash Rs.300-500 · FRP Rs.300-500.

THE POLICY: FRP is anti-theft. Only with proof of ownership (bill, Google account password known to the owner, SIM in the phone matching, ID). Put it in writing at the shop. UMT and free tools handle most; Samsung needs its own flows (Week 11).

Never: a phone that arrived "found" with an unknown Google account. That's stolen property - refuse politely and firmly.

Diagnosis:

1. Settings → battery usage - the runaway app or "Android system" spike.
2. Poor signal areas drain hard (phone boosts TX power) - explain.
3. Battery age/swelling = replace (2.2).
4. Heat + drain = see 2.14.
5. PSU test: current draw at idle vs. specs; a partial short drains even "off".
6. Fake/aftermarket battery with low real capacity - the shop trade issue: sell good batteries only.

Phone shows nothing at all, no charge animation: EDL/test-point entry (Qualcomm: 9008 port; MTK: preloader mode) + SP Flash Tool/UMT flash with correct firmware. Learn test points per model from online guides. This is the Week 11-12 skill - and the reason customers travel between shops.

When: a chip has cracked solder balls (drop damage on large BGA chips, boot issues traced to the CPU/PMIC). Process: remove chip with hot air 380°C + board preheat → clean old solder with braid + flux → clean pads → set the stencil → ball paste or balls+flux → hot air till balls flow → re-mount → reflow. Practiced on BGA-221 boards in Weeks 7-13 - never first-time on a customer board.