My Blues Jr Just Crapped Out

Discussion in 'Glowing Bottle Tube Amp Forum' started by HotRodSteve, Aug 13, 2019.

  1. HotRodSteve

    HotRodSteve Friend of Leo's

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    Went to plug in, it made a bad noise and no sound or lights. Any ideas?
     
  2. Chud

    Chud Poster Extraordinaire

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    Check the fuse? That pretty much taps my ability to troubleshoot high voltage items. Lol
     
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  3. JuneauMike

    JuneauMike Friend of Leo's

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    Also try the Amp Tech forum. Not only will they tell you it's not dead, but if it is dead, they'll recommend you convert it to something else. Like a Vox or Matchless

    Also, did you smell anything? Any obvious charring inside (look, but don't touch anything until you know how to drain filter caps)?
     
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  4. HotRodSteve

    HotRodSteve Friend of Leo's

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    Where's the fuse?
     
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  5. bcorig

    bcorig Tele-Afflicted Silver Supporter

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    My long lost brother!!
     
  6. bcorig

    bcorig Tele-Afflicted Silver Supporter

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  7. Chiogtr4x

    Chiogtr4x Friend of Leo's

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    Mine, which I played the heck out of since 2000, just did this in the Spring, right before a big gig- turned out to be the power Transformer!

    Thank goodness for knowing a great tech- he figured it out after 10-15 min. of trouble shooting, while I watched...
    Ordered the part, plus did a ' tone stack' mod. ALL BETTER!
     
  8. kubiakl

    kubiakl Tele-Meister

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    I had one where the power tube sockets came unsoldered a little. Heat + time + movement eventually took its toll. They're mounted on a circuit board. If I jiggled the power tubes around a little and crossed my fingers I could get it to work sometimes. I can't remember if the light came on before I jiggled them though and have since given the amp to someone else to mess with. He had a buddy resolder those sockets and now uses it all the time.

    Definitely something to try. It made a bad noise (a pop and crackle) when the tubes weren't making solid contact and you mentioned it making a bad noise when yours went out. Just be careful and don't touch the tubes, wiggle the little retainer thing and use a towel. It gets pretty toasty.
     
  9. kubiakl

    kubiakl Tele-Meister

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    Also, what he said - check the Amp forum, those guys know their stuff:

     
  10. JuneauMike

    JuneauMike Friend of Leo's

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    In the fuse holder.

    (This is not your amp, but it's close enough)
     

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  11. JuneauMike

    JuneauMike Friend of Leo's

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    Also, to state the obvious. Fuses don't just blow.

    If it turns out the fuse failed, then your next challenge has to be figuring out why.
     
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  12. HotRodSteve

    HotRodSteve Friend of Leo's

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    Okay, found a burnt out fuse so I'll assume it's the culprit. It's the fuse that says F2AL 250V. I swear I was only running 120V AC into the amp! All I need is a Wrigley's gum wrapper. Or a new fuse. But why would it burn out?
     
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  13. JuneauMike

    JuneauMike Friend of Leo's

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    There are a myriad of reasons. Many of which can be found in the Amp Tech center or (my personal favorite) Shock Brothers.

    If you've got a Wrigley's gum wrapper, then you're all set. Stick that sucker back in, turn it on, and poof got yourself a new amp.

    Wait, no. I meant to say "poof, go get yourself a new amp." Sorry, my mistake.



    (Whoa, what happened? This thread started in Bad Dog, now it's in a totally new forum. I'm slightly dizzy now)
     
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  14. Chud

    Chud Poster Extraordinaire

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    As Juneau noted, the fuse is more of a symptom rather than the cause itself. It's doing its job of protecting the rest of the amp by breaking the circuit. It may have been a momentary surge from your AC power when you plugged it in that did it, or it may be something that bumped, jiggled, or just plain broke loose that popped it. You can test the former and the latter easily by replacing the fuse, plugging it in, then turning it on again. If the fuse goes again, it's the amp. If it doesn't it *might* not be the amp. o_Oo_Oo_O

    Thus ends the sphere of my dangerous expertise in troubleshooting high voltage items. :lol::lol::lol:
     
  15. Dacious

    Dacious Poster Extraordinaire

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    How long have you owned the amp and how much use has it had?

    You blew a fuse - 99.9% it means there is a fault emerging. Probably worn out tubes. But it could be a number of things.

    Go get a new fuse for a buck - your guitar shop or Mouser or local electronics store will have one. Get a couple the same as came out.

    Take the tubes out and replace the fuse. If the fuse pops again - no power tubes - your transformer is probably toast. Tech time.

    If the fuse doesn't pop, amp light stays on, try turning the amp off and put your tubes back in.

    If the fuse pops when you turn amp on, you likely have bad power tubes - yes, they wear out and BJs run them hard. They can get cooked and distort inside so you get a short. Bingo - popped fuse.

    Get a new matched pair of power tubes, put them and another fuse in, you should be good to go. If the fuse pops again - tech time.

    These things are not heavy duty items. They do burn components out. Sometimes as a tube's going, it can crisp the bias resistors and/or they go and take the fuse.
     
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  16. idjster

    idjster VERY grateful member Silver Supporter

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    Heh! I think we all must be related! :lol:
     
  17. HotRodSteve

    HotRodSteve Friend of Leo's

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  18. JuneauMike

    JuneauMike Friend of Leo's

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    Your BJ should have two fuses. One may be F2A 250V and the other T5A 250V. F=fast and T=slow.
    It's important that you get the correct voltage and amperage of a fuse (well, actually you can use less amperage if you want) and that they are either fast acting or slow acting. That fuse is a safety net, it is supposed to absorb the punch if something downstream is wrong. If you get a higher rated fuse then you can damage the components that it was previously protecting.

    If you've got your fuse then you've got the back off. See if you can figure out which version of the BJ board you've got. Then look for the layout diagram in the service manual.
     
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  19. HotRodSteve

    HotRodSteve Friend of Leo's

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    I'll try a new fuse first. If it still craps out I'll take it to the next level, or just use my Pignose amp and take the BJ to the rifle range.
     
  20. Milspec

    Milspec Friend of Leo's

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    One of the big weaknesses on those amps (and many others today) are the ribbon conections to the tubes. Check to make sure there aren't any cracks or obvious damage.

    It may just be the fuse due to a voltage spike. I used to work for the local utillities company and I have seen some crazy spikes that only last a millisecond or 2, but it is enough to blow a fuse. I would also seriously consider using a different outlet until you test that as well.
     
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