Czy wolisz polską wersję strony elektroda?
Nie, dziękuję Przekieruj mnie tamHi, I’m having a serious issue with my Bluedio T7 Turbine headset. Here’s what’s happening:
1. Charging Failure & Short at battery terminal
- The battery won’t charge & stuck at 3.4v.
- The battery’s +/- terminals shorted and burned at one point.
- Oddly, the.components like resistors, fuses, capacitors, diodes, and ICs test fine (no shorts, physically damage or overheat).
2. Strange LED Behavior
- When I plug in 5V input, both red & blue LEDs light up together (should only be red while charging, blue after full charge in 2 hours).
- Test points:
- 5V & B+ read normal (~4.2V).
- Output near ANC shift-key IC is >3V.
- CPU voltage: 3.4V (some parts 1.8V–2V).
- Bluetooth IC: 2V–4V.
3. Weird Audio & Power Issues
- When charging, current draw is 0.3A, and the speaker makes crackling/looping noise.
- BT power switch works (ON = normal), but when turned OFF → ON, no voice prompt & Bluetooth isn’t detected.
- Tried different battery & speaker—same issue (noise persists).
4. What I’ve Tried
- ✔ Read the user manual repeatedly.
- ✔ Reset headset (hold multifunction + vol up/down)—blue LED won’t blink 3x.
- ✔ Checked Bluetooth settings on phone—still undetected.
- ✔ Replaced battery & speaker—no fix.
- ✔ Contacted Bluedio support—no reply for days.
- ✔ Asked in forums—no help (just told to "see a technician").
5. My Request for Help
- Since the built-in charging IC seems damaged, do you have a workaround circuit to charge the Li-ion battery manually?
- I can’t find the original IC on online market or at datasheet online.
• Yes – you can bypass the damaged on‑board charger and recharge the single‑cell Li‑ion pack with an external CC/CV charger such as a TP4056, MCP73831/32 or a laboratory power supply limited to 4.20 V.
• The battery must be disconnected from the headset PCB while charging.
• Set/verify the charge current to ≤ 1 C (typically 400–800 mA for the Bluedio T7’s ~500–800 mAh pouch cell).
• This only restores energy to the pack; it will not cure the deeper power‑management/logic fault that prevents normal operation.
1. Root cause chain
• The battery‑terminal short most likely overstressed the Power‑Management/Charging IC (PMIC) on the main PCB.
• PMIC failure explains every symptom you observe:
– Wrong LED sequencing (red + blue together = charger cannot determine state).
– Fixed 0.3 A from 5 V regardless of battery SOC = charger FETs shorted, CC loop open.
– Unstable rails (CPU 3.4 V instead of regulated 3.3 V, BT rail wandering 2–4 V) = buck/LDO section of PMIC no longer regulating.
– Crackling audio = rail ripple coupling into Class‑D amp and codec.
– No BT enumeration / voice prompt = MCU fails brown‑out reset.
2. Component checks “OK”
• Passive parts often survive; a latched‑up PMIC can look fine to a DMM yet be internally shorted.
• Bluedio frequently uses un‑marked QFN PMIC/charger combos (Silergy SY6918, ETA9697, Injoinic IP5306, etc.). These are hard to source and need hot‑air rework.
3. Remaining functional blocks
• Your ancillary test points (ANC shift‑key ≈ 3 V, BT rail > 2 V) prove 5 V is reaching the board, but regulation is lost.
• Even with an externally charged battery the headset may still refuse to boot if the PMIC cannot supply clean 1.2/1.8/3.3 V rails.
• TP4056 “Type‑C” boards with integrated DW01A+8205A protection now cost < US$1.
• More advanced drop‑in parts (BQ24075, IP5410) add thermal fold‑back, USB OTG boost and ship‑mode control – useful if you plan a permanent retrofit inside the cup.
• Consumer repairs increasingly replace entire PMIC sections with such modules when OEM parts are unobtainable.
Li‑ion charging profile
\[ I{\text{chg}}=\text{constant} \rightarrow V{\text{bat}}=4.20\text{ V} \rightarrow I{\text{chg}}<0.1\,I{\text{max}} \]
• TP4056 implements this CC/CV curve autonomously; the PROG pin resistor sets \(I{\text{max}}\):
\[ I{\text{max}}\,[\text{A}] \approx \frac{1}{R_{\text{PROG}}\,[\text{k}\Omega]} \]
e.g. 1 kΩ → 1 A, 2 kΩ → 0.5 A.
Typical wiring for an external module
USB‑5 V ─┬─ IN+ (TP4056) B+ ───► Battery +
└─ GND B- ───► Battery –
(red LED = charge / blue‑green LED = full)If you intend to keep the charger inside the headset:
• Remove the damaged charger IC or cut its B+ pin to avoid two chargers fighting.
• Feed TP4056 OUT directly to the battery pad; keep leads short (< 30 mm).
• Place an NTC (103AT, 100 kΩ) against the cell and connect to TEMP (if the module supports it) for extra safety.
• Li‑ion packs are subject to IEC 62133 / UL 2054. Any modification voids the manufacturer’s safety certification.
• Manual charging outside the headset should be done on a non‑flammable surface, under supervision.
• Transporting a modified device may breach airline regulations if the BMS no longer complies with UN 38.3.
1. Remove rear cup, unplug battery JST.
2. Visually confirm cell has its own protection PCB (DW01A/FS8205 combo). If not, use a TP4056 that includes protection.
3. Charge externally until TP4056 LED turns blue and multimeter shows 4.15–4.20 V.
4. Reconnect, power up.
• If headset still fails → PMIC/MCU damaged beyond field repair.
• If it boots → you can either:
a) continue external charging (inconvenient), or
b) embed the TP4056 permanently and route its USB‑C port to the original hole.
Challenges and mitigations
• Space: TP4056 boards are 17 × 26 mm – may require milling plastic.
• Thermal: linear chargers dissipate (5 V–4.2 V)×I ≈ 0.8 W @ 1 A; derate to 0.5 A or add copper foil.
• None of the above restores LED logic, battery gauge, ANC auto‑calibration or fast‑charge features.
• If the CPU flash is corrupted or the PMIC’s enable pins are stuck, even a perfect battery will not resurrect the unit.
• Replacement PCBs for Bluedio T7 are not sold; economics may favour a new headset.
• Reverse‑engineer the PMIC: trace its pin‑out, compare against SY6918/IP5306 reference designs – could allow a pin‑compatible drop‑in.
• Study open‑source headphone projects (e.g., Open‑WRT‑Audio) for future DIY designs with replaceable modules.
• Monitor repair communities (iFixit, BadCaps, EEVblog) – successful T7 PMIC swaps may surface.
The shorted battery likely destroyed the Bluedio T7’s combined charger/PMIC, causing mis‑regulated rails, LED anomalies and system crashes. Sourcing that custom IC is impractical, so the only realistic workaround is to disconnect the pack and charge it externally with a proven CC/CV module such as TP4056 (or MCP73831, BQ2407x). This will safely bring the battery to 4.2 V but cannot guarantee the headset will function, because the same fault probably affects the logic supply rails. If the unit still misbehaves after inserting a freshly charged cell, the main PCB is beyond economical repair.