Persamaan Transistor D998 B778 Review

Transistor driver (biasanya ukuran TO-220 seperti D669/B649) harus diganti jika D998/B778 short. Driver yang rusak akan membunuh transistor final baru meskipun sudah menggunakan persamaan yang tepat.

When D998 or B778 transistors fail, it is usually due to one of three causes:

  • Thermal Runaway: Caused by improper biasing or a failed heatsink compound. The transistor gets hot, draws more current, gets hotter, and eventually destroys itself.
  • Leakage: The transistor does not fully turn "off." This creates distortion in audio (crossover distortion) or excessive heat even when the device is idle.

    • Karena banyak yang mencari persamaan, pedagang nakal menjual transistor "dijamin original" tapi palsu. Ciri-ciri fisik: Persamaan Transistor D998 B778

    | Ciri | Original Sanyo | Palsu (Aspal) | | :--- | :--- | :--- | | Berat | Berasa berat (chip tembaga besar) | Ringan seperti plastik | | Kaki (lead) | Tebal, mengkilap, keras | Tipis, mudah bengkok, kusam | | Tembaga belakang | Pola serat tembaga kasar | Halus seperti cermin murah | | Kode produksi | Ada lot number (misal: 9N2) | Hanya tulisan D998 besar | | Uji hFE (dengan Ic 1A) | >60 | <30 |

    Test paling jitu: Gunakan transistor tester atau power supply 24V, beban lampu 5W/12V. Jika panas berlebihan tanpa sinyal, itu palsu. Thermal Runaway: Caused by improper biasing or a

    Fakta: Meskipun lebih bagus (MT-200 casing besar), ukuran fisiknya lebih besar. Kemungkinan tidak muat di PCB asli D998/B778. Jika ingin upgrade, Anda harus mengebor ulang lubang PCB dan mengganti mika isolator.

    The 2SD998 (NPN) and 2SB778 (PNP) are a complementary pair of power transistors widely used in audio power amplifiers, particularly in the output stages of high-fidelity (Hi-Fi) stereo systems, home theater receivers, and professional PA amplifiers. Known for their high current handling and wide Safe Operating Area (SOA), this pair has become a standard in many Japanese-brand amplifiers from the 1980s–2000s (e.g., Pioneer, Kenwood, Technics, and Sansui). Leakage: The transistor does not fully turn "off

    However, as these original parts become obsolete or difficult to source (especially genuine ones), finding a suitable equivalent (persamaan) is critical for repairs and DIY projects.