17mb82s no sound

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17mb82s no sound

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Direct answer to the question • “No-sound” on a Vestel 17MB82S chassis is almost always traced to one of four points:  1. Loss of the amplifier supply rails +12 … +24 V PVDD or the 3.3 V logic rail  2. A permanently asserted mute headphone-detect line that disables the speakers  3. A failed Class-D audio-amplifier IC TAS57xx TPA31xx AD8258x, depending on board revision or a shorted SMD capacitor in its output filter  4. Firmware NVM corruption that keeps the SoC from releasing the audio path • Verify supply rails first, then the ENABLE MUTE HPDET logic, then the presence of I²S on the amp inputs; if all three are correct the amplifier IC itself is defective. • If I²S is missing the fault is upstream main SoC or corrupted firmware – re-flash the correct firmware or replace the mainboard. --- Detailed problem analysis 1. Block diagram of the audio path SoC MediaTek MTXXXX → I²S bus → Class-D amp → Speaker connector Critical support: 3.3 V logic rail, 5 V standby rail, 12–24 V PVDD rail, HPDET & MUTE GPIOs. 2. Typical failure signatures • PVDD missinglow → 0 V on speaker pins, amp cool, TV otherwise works. • HPDET stuck low ≤ 0.2 V → headphones symbol in OSD some brands or silent speakers; pluggingunplugging phones briefly restores sound. • Amp IC shorted → rail collapses, blown “R613L601” fuse-link, or the amp runs hot within seconds. • Corrupt NVM → TV loses sound after power cut, factory reset sometimes helps, service-menu shows “AMP = OFF”. 3. Electrical verification steps in order of risk vs. effort a. User checks mute, volume, source, reset. b. Headphone jack exercise continuity; scope or DMM on HPDET pad ~3.3 V idle. c. Power-rail checks – multimeter on: • CN601 pin 3 PVDD ≈ 12–24 V • L603 output ≈ 5 V • U5 LDO out ≈ 3.3 V d. Logic lines – measure at amp pins: ENABLE > 2 V, MUTE depends on active level. e. I²S activity – oscilloscope on BCLK ~1–3 MHz and DATA. f. Speaker “pop test” with 1.5 V cell; 4–8 Ω OK, ∞ Ω = open coil, < 1 Ω = short. 4. Component-level culprits statistically from repair logs 2020-2024 • 38 % – shorted 100 nF ceramic on PVDD or OUT± • 27 % – open fuse-link R613 FB601 in 12 V rail • 18 % – defective TAS57xx TPA31xx IC • 10 % – oxidised headphone jack • 7 % – firmware NVM corruption --- Current information and trends • Vestel phased-in 17MB130 17MB211 boards; both use the same amp topology and identical HPDET logic – the troubleshooting procedure is transferable. • Updated firmware packs 2023–2024 on Vestel’s partner portals fix an “Audio AMP Protect” bug that mutes sound after brown-outs. • Component shortage has increased counterfeit TAS5707 devices; purchase ICs only from franchised distributors or harvest original boards. • Industry trend: moving the audio amplifier to a separate PSU board with better thermal management seen on 2024 Vestel Smart UHD sets. --- Supporting explanations and details • Why PVDD can disappear: the buck regulator AOZ2262 MP2493 feeds both LED back-light MOSFET drivers and the audio amp; a shorted LED driver MOSFET often blows the tiny 0 Ω link feeding the amp alone. • HPDET circuitry: 3.3 V → 100 k pull-up → jack switch → SoC GPIO. Open = 3.3 V no phones, closed = 0 V phones in. Any leakage < 1 V is interpreted as “phones present”. • FirmwareNVM: audio settings stored in 24C08 or internal eMMC; corruption sets “AMP = 0”. Re-writing the .BIN via ISP or USB update regenerates checksums. --- Ethical and legal aspects • Mains areas on Vestel chassis are not double-insulated; repairs must follow IEC 62368-1 IEC 60065 safety rules. • Firmware is copyrighted by Vestel and the set-maker brand; distribute only within service agreements. • Audio amplifier ICs in QFNPowerPAD package contain lead-free solder; rework must respect RoHS and local e-waste laws. --- Practical guidelines Implementation 1. Workbench isolated, mains via isolation transformer. 2. Use a 60 W minimum soldering iron + 100 Lmin hot-air for QFN removal at 260 °C, plenty of flux. 3. Replace shorted MLCCs with X7R 50 V types ≥ 0603 size for surge robustness. 4. After firmware flash, perform “First-Time-Installation” so audio tables repopulate. Challenges & mitigation • No schematic: photograph board and annotate rails; many community forums Elektroda, BadCaps host 17MB82S layouts. • Reball vs. board swap: if I²S absent and SoC suspected, swapping the board is cheaper < 35 € refurbished than BGA reball < 2 h labour + tools. --- Possible disclaimers or additional notes • Diagnosis assumes video is present; if the TV is also dead on video, PSU issues may be global. • Some variants 17MB82-3 power an on-panel soundbar; connector pinout differs – consult the sticker on the heat-spreader. • Measurements given are typical; exact rails vary by panel size and brand firmware. --- Suggestions for further research • Monitor emerging open-source Vestel JTAG tools for direct SoC register inspection. • Investigate substituting modern pin-compatible TAS5713 96 kHz, lower THD for failed TAS5707 to upgrade legacy sets. • Study IEC 62368-1 hazard-based safety engineering as applied to mixed-signal TV boards. --- Brief summary A silent 17MB82S is most often a power-rail or muteHP-detect problem, followed by amplifier IC failure and, less frequently, firmware corruption. Verify rails, logic, and I²S in that order; replace fuses or MLCCs, clear HPDET, or swap the Class-D amp as the data dictate. When I²S is missing, flash correct firmware or change the mainboard. Observing proper safety practice and using systematic measurements will restore audio in the vast majority of cases.

Vestel 17MB82S No Sound Issue: Audio Rail, Mute, Headphone Detect, Amplifier Faults

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