Dead Dual Rectifier

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by les_paul, Dec 6, 2018.

  1. les_paul

    les_paul Member

    Messages:
    578
    Joined:
    Oct 16, 2009
    I was playing tonight when I lost all volume from the amp save for a soft sputtering sound when playing. Here's what I've done so far:

    -Made sure it wasn't channel specific; same in all channels.
    -Plugged into the effects return; no sound.
    -Bypassed loop altogether; nothing.
    -Replaced power tubes; nothing.
    -Replaced rectifier tubes one at a time; nothing.
    -Replaced preamp tubes one by one; nothing.
    -Ruled out guitar, cables, etc.
    -Switched so solid state rectifier; nothing.

    Aside from sending it off for warranty repairs (nobody even close to me) what should be my next steps? Do rectifier tubes fail in pairs? If so, I'll need to grab another rectifier tube to test two new rectifiers simultaneously. I have not seen any arcing and all power and rectifier tubes light up when powered on. I didn't see or smell smoke.
     
  2. 0010 0001 0011 1111 1110

    0010 0001 0011 1111 1110 Member

    Messages:
    938
    Joined:
    Oct 6, 2013
    Location:
    The brake light district.
    Have you tried a different speaker?
     
    Thumpalumpacus likes this.
  3. les_paul

    les_paul Member

    Messages:
    578
    Joined:
    Oct 16, 2009
    Yep no go on that front.
     
  4. 0010 0001 0011 1111 1110

    0010 0001 0011 1111 1110 Member

    Messages:
    938
    Joined:
    Oct 6, 2013
    Location:
    The brake light district.
    It's under warranty, send it in. I think you've done all you could do without voiding the warranty. By any chance, are there any fuses that are accessible for you to check?
     
    Thumpalumpacus likes this.
  5. les_paul

    les_paul Member

    Messages:
    578
    Joined:
    Oct 16, 2009
    Just the mains fuse which is fine.
     
  6. Thumpalumpacus

    Thumpalumpacus Member

    Messages:
    2,414
    Joined:
    Dec 16, 2011
    Location:
    Texas
    Check the fuse. If a power tube has failed, the fuse will likely blow, and changing tubes at that point will still deliver no sound because the fuse has interrupted the circuit.

    ETA: never mind, you've checked that already.
     
  7. gldtp99

    gldtp99 Member

    Messages:
    2,507
    Joined:
    Dec 23, 2005
    Location:
    Texas
    Dual Recs are complex amps.

    They have a switch for just about anything you could possibly imagine.

    To operate the FX Loop one almost needs a major university course in the subject.

    So when they break down you need to take them to an Authorized Mesa Repair Facility for proper troubleshooting/repair.

    And pay them to fix it.

    Troubleshooting a Dual Rec is not something that is easily done online.

    You've already done the quick/easy checks.

    Now take it to the Mesa Repair Center that is most convenient for you.
     
    pdf64 likes this.
  8. wsaraceni

    wsaraceni Member

    Messages:
    7,144
    Joined:
    Nov 2, 2003
    what version of the dual rec head is it?
     
  9. NortheastHick

    NortheastHick Supporting Member

    Messages:
    5,787
    Joined:
    Nov 2, 2006
    Location:
    22 Acacia avenue
    It sounds to me like maybe one of your power tubes red plated and took out a screen grid resistor. Good luck. That's an odd one.
     
    donnievaz likes this.
  10. les_paul

    les_paul Member

    Messages:
    578
    Joined:
    Oct 16, 2009
    I'll open up less complex amps for such repairs but not this one. I don't have a Boogie service tech anywhere close and I sent it back to where I bought it from for repair (they are licensed). I can't wait to hear what's wrong with it. It'll be a little while, though. Not like I don't have other amps to play.

    I've only ever seen one other problem with a Boogie. I worked for a dealer and we got a Lone Star Classic when they were a brand new line. We flipped it on and it arced like no other. We replaced all power tubes and the rectifier, flipped it on, and saw the same thing. Never did find out what was wrong but they were quick to get as a new one since the line was brand new.

    Back to this Dual Rec: I didn't see a light show when it failed and all power tubes and rectifiers lit up in addition to the power and channel lights. Any further thoughts?
     
  11. pdf64

    pdf64 Member

    Messages:
    5,188
    Joined:
    Aug 9, 2008
    Location:
    Staffordshire, UK.
    I think that these amps use a screen grid resistor per power tube. If a screen grid resistor blows, the tube will go deep into cut off, but all 4 power tubes would have had to loose screen grid voltage for that symptom to manifest.
     
    les_paul likes this.
  12. Bloozey

    Bloozey Member

    Messages:
    18
    Joined:
    Nov 21, 2014
    Does it happen in half-power and full-power mode ?
    Also check the PI
     
  13. Jerry

    Jerry Supporting Member

    Messages:
    560
    Joined:
    Nov 5, 2007
    Location:
    Central,IL
    Do you have other amps with effect loops? Try Dual Rec preamp out to another power amp in. Other preamp out to power amp in of Boogie.
     

Share This Page