Egnater Mod 50 problems

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by Miles Long, Feb 23, 2009.

  1. Miles Long

    Miles Long Member

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    There is a light by the bias points in the back of the amp on the left side that says tube failure. I replaced the output tubes and the light is still on. The amp breaks up on the clean channel with a harsh sounding distortion. Phase inverter perhaps?
     
  2. WaltC

    WaltC Member

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    When you replaced the output tubes did you check/adjust the bias on the new tubes? If not, then they can be enough out of "whack" to give you the indications you're getting. If you did and you still get the error, then it is very possible that something in the amp has failed (screen resistor, something in the bias circuit, etc.) and needs to be repaired.

    Probably time for a trip to the amp doctor.
     
  3. RockStarNick

    RockStarNick Supporting Member

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  4. Pat Healy

    Pat Healy Member

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    Have you called Egnater? Bruce was very helpful in working through some problems with my Mod50.
     
  5. Miles Long

    Miles Long Member

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    Tung SoL 5881.
     
  6. Miles Long

    Miles Long Member

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    I gave Jeff an e-mail today. I haven't had much luck getting through on the phone line.
     
  7. Miles Long

    Miles Long Member

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    Yes, the bias is 23 ma. Maybe a fuse? I'm not the most tech saavy, lol.
     
  8. WaltC

    WaltC Member

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    23 ma is pretty low even for 5881s. Something closer to 32-38 ma (assuming around 430V on the plates or so) would be more like it. It's possible if you bring the bias up to that range that the light will go out. I've not worked on that model Egnater, but Bruce is very helpful and I'm sure he'll point you in the right direction.
     
  9. mooreamps

    mooreamps Senior Member

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    Impossible to diagnose without a schematic, since the a light being "on" indicates a failure.

    -g
     

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