2245 left channel static

Discussion in 'Marantz Audio' started by DucatiDave, Jun 13, 2018.

  1. DucatiDave

    DucatiDave New Member

    Messages:
    37
    Hello to all,

    I recently picked up an unloved 2245 from an acquaintance of mine. I am normally on the Sansui forum and I have re-capped a Sansui 1000a, so I am very familiar with electronics testing and repairs. But when this became available I thought it would be the perfect opportunity for me to experience the Marantz sound and compare it to my Sansui gear.

    I cleaned up and deoxed all the 2245 switches and faders. It plays beautifully for about 30 minutes at which time the left channel output goes to virtually nothing and it is replaced with very loud static and popping. This noise takes place on both the main and remote outputs. Tone control, volume, balance, and all switches have ZERO effect on the static and popping, except for the main and remote switches, they work and still turn the speakers on and off. The static and popping are on all inputs as well, phono, aux, FM, AM, tape.

    Due to the sound not changing with any of the input controls, that leads me to believe it is in the amp section right before the signal goes to the speakers. Output transistors? Caps? Any places I should start looking? Any help would be greatly appreciated. I have found a schematic on Hi-fi engine and it looks like board P750 (L) is where I should be looking.

    Thanks
    Dave
     

     

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  2. Steven Tate

    Steven Tate AK Subscriber Subscriber

    Messages:
    2,740
    Location:
    N. Richland Hills, TX
    Pull the Pre Out/Main In jumpers and run it for a while and see if it still makes the noise. That can confirm a bad main amp. One other place you might give extra attention is the Tape Monitor switch. Give it three or four good flushes with Deoxit and work the switch 50 times. The signal pretty much always goes through this switch, and if it's dirty, it can cause the kind of noise you are experiencing.
     
  3. DucatiDave

    DucatiDave New Member

    Messages:
    37
    Pulled the pre and main jumpers and the noise went away. So it is definitely in the pre amp section. Played around a little more and found that the high and low filters altered the static yet the tone controls did not. Which narrows it down to the 400 board after the tone controls but before the filters.

    It’s funny, sometimes it will have static and popping when I first fire it up, I can hear the relay click and slowly the static will start and get louder. Other times it takes an hour of playing before the static comes in. Old caps that are reconditioning themselves? Faulty transistors?

    Dave
     
  4. DucatiDave

    DucatiDave New Member

    Messages:
    37
    Transistor on the tone board, h404. Soldered a new one in and everything is good to go.
     
  5. Steven Tate

    Steven Tate AK Subscriber Subscriber

    Messages:
    2,740
    Location:
    N. Richland Hills, TX
    Nice work! Enjoy it. :thumbsup:
     

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