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Case # 564867 .  07/20/2025 . Sansui 9090db .  No sound.  No relay click.

Tested output transistors and found 3 transistors   2sb554   is out and 3 resistors and 2 transistors on driver board are dead too. Replacement parts in driver board was easy to find and no problem. But   2SB554   was a big pain. I have tried 2 different sellers from Ebay with negative experience. They all selling junk copy of original Toshiba transistors.  They selling transistors  2SB554    with fresh printed red numbers on them. They look new and freshly made .
They are junk !!!!!

fake and original Toshiba transistos

 

After negative experience i used original 2N6609 FROM MOTOROLA   WITH GOOD RESULTS.   I replaced all 4 transistors 2sb554 with 2N6609.    Unit tested few days with real sound , temperature – ok, dc offset ok , BIAS -OK, frequency respond perfect. They have same NTE  numbers  and pinout    and working good.  NPN  transistors  still original and  were not  changed.

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Case # 741123.  07/15/2025  Tube Fisher Allegro A-19 console. Low sound on both channels.

 

Case # 741123.  07/15/2025  Tube Fisher Allegro A-19 console. Low sound on both channels.

Interesting unit from Fisher.  Turntable, tuner and amplifier in one  cabinet.

After cleaning and testing found one low/ middle range speaker in right door is dead. Measure  8 ohms coil but produce 15% of sound only.   One  preamp vacuum tube 12ax7   glows purple color inside  and shots down  sound in both channels. Filter and power supply capacitors after 60 years still ok.   60 years ago people know what word QUALITY  means.  Fisher use 2 door hinges  as a speaker output terminals for speaker wires.  That is unbelievable .  Speakers connected to door hinges and amp output connected to door hinges also. Door hinge  is conductive wire  for speaker . That is how they solve problem amp connection  with speaker inside the door .  Genius !!! I Love it  !!!!!   If  you  have  extra  speaker you can connect it  to door hinges directly .

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Case # 560034 .   07.11.2025 .   Linn Linto preamplifier.  No power.

Interesting unit from European electronics  style craftsman and technical design . 75% of this unit is power supply , promotes high attention to quality of voltages power supply generates ,  detailed components management work on board , good , long lasting components used , power supply shielding  is extreme.  Even all internal wires insulated from chassis by cork material.  Simple schematic in signal path  line.
  Power supply standard  SMPS ,   in opto-isolator section they use  opto coupled transistor instead  diode .  Two steps voltages transformation  and filtration used in this unit  . General  SMPS  Power supply generates – + 14v,  – 14v,  +9 v , – 9 v  .

Minuses – shielded power supply  but no ventilation holes at all  ( internal heat in small closed box kills capacitors )  ,  using  SMD capacitors (small to save space but not reliable  for long term ) .

We offer repair service for this model in repair  service section on front page.