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Thread: blowing fuses on power up, Deluxe Reverb

  1. #1
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    blowing fuses on power up, Deluxe Reverb

    1973 Fender Deluxe Reverb.
    I have always used the on/standby switch in what I thought was the correct manner, but now when I turn the "On" button I blow the fuse within a couple seconds.
    Ground switch is in the center position, is that correct?
    Amp was serviced and recapped last fall.
    Any ideas for me or does it need to go back to the service tech?
    Thanks, Gary

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    Forum Member Don's Avatar
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    Re: blowing fuses on power up, Deluxe Reverb

    Does it blow the fuse if you turn on the power switch with no tubes installed in the amp?

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    Re: blowing fuses on power up, Deluxe Reverb

    I have not tried that, I will test and repost to this thread.
    If it stops blowing fuses with no tubes, do I put them back one at a time until it blows the fuse again? Is there any order, I need to follow?
    Thanks, Gary

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    Forum Member Don's Avatar
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    Re: blowing fuses on power up, Deluxe Reverb

    I would start with the rectifier and then the power tubes. Was the rectifier replaced with a modern rectifier when the amp was serviced last fall?

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    Re: blowing fuses on power up, Deluxe Reverb

    Quote Originally Posted by Don View Post
    I would start with the rectifier and then the power tubes. Was the rectifier replaced with a modern rectifier when the amp was serviced last fall?
    It did end up being the Rectifier Tube. I remembered
    that I had a solid state rectifier, plugged it in and that took care of the problem. Thank you. Gary

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    Forum Member Don's Avatar
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    Re: blowing fuses on power up, Deluxe Reverb

    Quote Originally Posted by glmoore0001 View Post
    It did end up being the Rectifier Tube. I remembered
    that I had a solid state rectifier, plugged it in and that took care of the problem. Thank you. Gary
    That's great! Be careful running the amp with a solid state rectifier- it can allow the B+ voltages to be way too high. At the very least, the bias will need to be checked. At the worst, the voltage can be higher than the tubes can handle.

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    Forum Member vinyl's Avatar
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    Re: blowing fuses on power up, Deluxe Reverb

    Quote Originally Posted by Don View Post
    That's great! Be careful running the amp with a solid state rectifier- it can allow the B+ voltages to be way too high. At the very least, the bias will need to be checked. At the worst, the voltage can be higher than the tubes can handle.
    Once again, very solid advice from Don. The first thing to do would be to replace the rectifier tube with a 5U4GB. A solid state rectifier could raise the plate voltage to the power tubes by as much as approximately 35 volts. In any case it would require a bias check, if not an adjustment.

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