Pioneer m90 issue

Discussion in 'Pioneer Audio' started by Widzew83rts, Feb 11, 2019.

  1. Widzew83rts

    Widzew83rts New Member

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    21
    Hi

    I have a pioneer m90 , and there is a problem with dispay , display on the left side is lower than right side, sometomes left side disapire. Both chanels plays fine. I checked fuses they are ok
     

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  2. avionic

    avionic " Black Knights " F-15 Eagle Keeper Subscriber

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    Welcome to AK... Might get lucky and just have a bad solder connection on the display board.
     
  3. avionic

    avionic " Black Knights " F-15 Eagle Keeper Subscriber

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    Location:
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    AWZ-2041 board Circuitry containing IC401,402 and 403.Check solder connections.
     
    Last edited: Feb 11, 2019
  4. Widzew83rts

    Widzew83rts New Member

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    21
    Do you think if this is broken thas may be the issue? Please check picture
     

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  5. MattiaM

    MattiaM Member

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    That is the lamp indicating that the amplifier is not in protection mode. Even if open, it should have no influence on the meters.
     
  6. Widzew83rts

    Widzew83rts New Member

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    Do you know where can i get this lamp? Unther this lamp it PL 402
     

     

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  7. MattiaM

    MattiaM Member

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    In my recent M90 restoration I used successfully an 8V 170mA axial lamp (20mm in length). You can easily find it online.
     
  8. Widzew83rts

    Widzew83rts New Member

    Messages:
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    Ok thank, do you think the meters are not working corectly becouse i didnt conect the speaker yet? I just plug the amplituner and conect the phone to check if both canals are working
     
  9. MattiaM

    MattiaM Member

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    Location:
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    if the input signal is the exact same for both channels, the meters should display the same signal level. I would not recommend trying that without a load at the speaker terminals. If you are worried there are issues with the amplifier that might ruin your speakers, then use an 8 ohm dummy load with adequate power dissipation (that amplifier can produce 200W per channel into an 8 ohm load, so you will need something very beefy).

    With a load attached to the speaker terminals, if you don't have a signal generator, you can use your phone as signal generator; there are on YouTube videos that have frequency sweeps or individual frequencies (e.g. 440 Hz, 1 kHz) at a predefined output, so that you can be sure the signal reaching both channels is the same. With that, if you still observe differences in the L and R power meters, you have an issue somewhere.
     

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