Results 1 to 3 of 3

Thread: Fender ‘69 Bandmaster - Silence w/ Negative DC Voltage!?

  1. #1
    Forum Member
    Join Date
    Aug 2020
    Posts
    2

    Fender ‘69 Bandmaster - Silence w/ Negative DC Voltage!?

    First time posting, I’ve got a drip-edge Bandmaster and did some work on it (New tubes, all new electro caps, Added master volume, replaced some resistors, etc.). Everything worked fine and I went to make my measurements to bias, then turned off the amp to measure plate resistance and...

    When I turned it back on no sound came out. The tubes glow but the OT center tap and DC voltages are now *negative*. -.433v. The tubes don’t get hot. I’m thinking a blown transformer, but I would like to know if this is a simpler problem first before pulling things out.

    ]I’ve switched tubes, speaker wires and cabs, guitars and cables, scanned/shaken inside, all to no avail. Any help here would be greatly appreciated and I can do more measurements if needed.

  2. #2
    Forum Member CoyotesGator's Avatar
    Join Date
    Jul 2012
    Location
    The Institute for the Very, Very Nervous
    Posts
    847

    Re: Fender ‘69 Bandmaster - Silence w/ Negative DC Voltage!?

    Recheck your work, post some pictures, and welcome to the group!
    What happend?
    Who let the magic smoke out?

  3. #3
    Forum Member
    Join Date
    Aug 2020
    Posts
    2

    Re: Fender ‘69 Bandmaster - Silence w/ Negative DC Voltage!?

    Quote Originally Posted by CoyotesGator View Post
    Recheck your work, post some pictures, and welcome to the group!
    I actually figured it out. I wired a 68 ohm 5 watt resistor from the diode chain into the power filter at the suggestion of Rob Robinette and that resistor failed. I removed it and it’s all good now!

    THE END

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •