Blew a fuse tonight at rehearsal. Heartbreaker

Discussion in 'Amps and Cabs' started by michael.e, Sep 14, 2018.

  1. michael.e

    michael.e Supporting Member

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    So I have been using my Heartbreaker with my band. Sounds awesome.

    I just put in a new set of Mesa 6l6’s about a month ago.

    A week or so ago, my little guy came in to the studio and flipped the standby switch on and off. Blew a fuse. I replaced it with a proper fuse and I have had no issues. I play a bit loud at home and nary a hiccup. Tonight at rehearsal which lasted a couple hours, the amp performed perfectly. After rehearsal, I stuck around and wound the amp up. Sounded glorious. I was at loud gig volumes. Amp was not even half way up.
    I keep it in tube recto mode all the time and variac switch up to full power and also keep it in the “Bold” mode.

    After about 30 seconds of glorious loud volume, the amp died. Fuse blew.
    I got it home and followed Mesa’s direction for trouble shooting tubes.

    Replaced fuse with proper size unit.
    Pulled all tubes, power and recto. Put the recto switch in Silicone Diode mode. Amp turned on and stayed on. Per Mesa, this eliminates any issues with the circuit. On to the tubes..

    I installed the recto tube back and set it to recto tube mode. Powered up and flicked the standby. No arcing or flashes from the recto tube and the amp stayed stable fully powered up.

    Next, I reinserted each power tube one at a time. No arcing or flashing. All power tubes appeared to be operating at the same level.

    Per Mesa, this is how you determine a bad tube.

    So no tubes seem to be bad, now what..

    I put the amp in to Silicone Diode mode and will play it hard tomorrow to see if the fuse blows again. If it does, I will run the head up to Mesa for a service I guess.

    My question now is, can a recto tube arc or temporarily fail if im running the amp hard? Either from vibration, or electrically from running the amp hard?

     
    Last edited: Sep 14, 2018
  2. CaliCaveMan

    CaliCaveMan Supporting Member

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    So, it's interesting that you mention this issue....

    I have a Roadster that I have had for many years and gigged with. I was at a couple rehearsals last year and the amp literally cut out, but the fuse did not blow. I contacted Mesa and they started down the path of could be a bad power source not giving enough current or spiking or something which caused the amp to shut off. This of course wasn't the case. I ended up taking it to Mesa and they were having issues finding the problem until at last they checked the fuse receptacle. It had corroded to the point that it was causing a disconnect after running for enough time to warm up I guess. So, a $3.00 part cost me a substantial service fee, but the problem was found and it's been fine since.

    I'm not saying this is your problem, but based on your testing so far, and the amps age, it might be worth checking for some corrosion on the fuse receptacle. Otherwise, you probably should take it to Mesa and have them check it out.
     
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  3. sickboy79

    sickboy79 Member

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    Might seriously be worth trying swapping preamp tubes. You never know.
     
  4. gunslinger

    gunslinger Member

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    I don't think preamp tubes cause a fuse to blow.
     
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  5. Aaron Mayo

    Aaron Mayo Member

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    Are you inserting power tubes while in standby or on? I can’t tell from your post.

    I had a pair of Mesa 6l6 that would blow a fuse on 2 different amps (50cal and express) when the amps were switched from standby to on. The pair went in the trash as I concluded there was a short in one of the 6l6s.
     
  6. ericb

    ericb Silver Supporting Member

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    Personally what I'd do at this point, is try it for extended periods of time at loud volume on the SS rectifier setting (if the Heartbreaker has that , like my Tremoverb) . . If it does not have any issues at all, I'd then change my Rectifier Tube, and try it again using "Tube Rectifier' setting.. . That will be your easiest/cheapest/do-it-yourself analysis and recourse. If it doesn't blow after that, you fixed your problem as the bad rectifier tube was causing the fuse to blow, and yes a rectifier tube can be functional but no good. Good luck

    Eric
     
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  7. De Batz

    De Batz Member

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    I had a period when my HB would blow fuses coming off standby, but only on the valve rectifier setting. There were some other components in the chain that needed replacing as well as the valve rectifier (not other valves) because it had damaged them when it went bad.

    So you might not be just replacing valves until it works again, and you'll need a competent person to help you with that if it keeps blowing fuses. Mine never went as a result of being played loud. It was when it came on, or not at all.

    Having said that, I've since had perhaps 15 years of more-or-less repair-free service from the HB since then. It seems to be a sound design. Mine, I think, was damaged by being switched on-and-off rapidly by someone who was using it when I left it at a shared rehearsal room (in the university! Savages!).
     
  8. michael.e

    michael.e Supporting Member

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    Thanks for the replies. Yes, per Mesa’s instructions, I turn off the amp all the way before inserting tubes. I’m going to run the amp through its paces today with the SS rectifier engaged. I hope it’s only the recto tube. Going to give Mesa a call anyway to today to say hi.

    How much different do you think a high zoot NOS tube would make in a more complicated circuit like this?
     
  9. michael.e

    michael.e Supporting Member

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    1 hour with SS diodes and all good.
     
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  10. CaliCaveMan

    CaliCaveMan Supporting Member

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    Did you call Mesa? What did they say?

    Nevermind, it's Friday, nobody is there today.
     
  11. guitarjazz

    guitarjazz Member

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    Inserted tubes one by one? Seems odd.
     
  12. michael.e

    michael.e Supporting Member

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    What seems odd about it? How else are you going to absolutely determine that it is one tube that is the problem?

    No issues thus far with using the SS recto. Must be the tube. I hope.
     
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